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This option proposes: Remove all rendezvous-point configuration from an ASM sparse-mode deployment and assume that every receiver automatically knows each source location. It addresses the different topic PIM sparse mode RP shared tree and shortest path transition, not the directly tested PIM dense mode flooding and prune mechanisms failure in the stated incident (After an access VLAN removes its last receiver, operations sees multicast continue briefly and needs to interpret prune and refresh behavior.).

This option proposes: Assume that configuring a multicast source anywhere in the network automatically populates IGMP membership on a VLAN where no receiver has joined. It addresses the different topic IGMP querier membership reports and group timeout, not the directly tested PIM dense mode flooding and prune mechanisms failure in the stated incident (After an access VLAN removes its last receiver, operations sees multicast continue briefly and needs to interpret prune and refresh behavior.).

This option proposes: Attempt to manipulate a remote ISP's outbound path by expecting an internal LOCAL_PREF value to be automatically carried over eBGP advertisements. It addresses the different topic BGP LOCAL_PREF within one autonomous system, not the directly tested PIM dense mode flooding and prune mechanisms failure in the stated incident (After an access VLAN removes its last receiver, operations sees multicast continue briefly and needs to interpret prune and refresh behavior.).

This option proposes: Diagnose outbound path choice across iBGP speakers using locally distributed LOCAL_PREF values. It addresses the different topic BGP LOCAL_PREF within one autonomous system, not the directly tested PIM sparse mode RP shared tree and shortest path transition failure in the stated incident (A regional site can reach multicast source addresses by unicast but its IPTV stream never starts because the PIM-SM RP mapping is inconsistent.).

This option proposes: Separate any-source group subscriptions from IGMPv3 source-specific multicast membership when implementing an SSM service. It addresses the different topic IGMPv3 source-specific selection and SSM, not the directly tested PIM sparse mode RP shared tree and shortest path transition failure in the stated incident (A regional site can reach multicast source addresses by unicast but its IPTV stream never starts because the PIM-SM RP mapping is inconsistent.).

This option proposes: Explain how PIM dense mode initially distributes traffic and then prunes interfaces lacking downstream receivers. It addresses the different topic PIM dense mode flooding and prune mechanisms, not the directly tested PIM sparse mode RP shared tree and shortest path transition failure in the stated incident (A regional site can reach multicast source addresses by unicast but its IPTV stream never starts because the PIM-SM RP mapping is inconsistent.).

This option proposes: PIM-DM generally follows a flood-and-prune model, building source-based multicast distribution where an interface without interested downstream receivers can be pruned to reduce unnecessary traffic. It addresses the different topic PIM dense mode flooding and prune mechanisms, not the directly tested PIM sparse mode RP shared tree and shortest path transition failure in the stated incident (A regional site can reach multicast source addresses by unicast but its IPTV stream never starts because the PIM-SM RP mapping is inconsistent.).

This option proposes: IGMP reports express receiver interest in multicast groups and a querier maintains group membership state; without appropriate reports or queries a router can age out forwarding toward a segment. It addresses the different topic IGMP querier membership reports and group timeout, not the directly tested PIM sparse mode RP shared tree and shortest path transition failure in the stated incident (A regional site can reach multicast source addresses by unicast but its IPTV stream never starts because the PIM-SM RP mapping is inconsistent.).

This option proposes: Routing protocols and static configuration contribute candidate routes to the routing information base, while the forwarding information base contains resolved next-hop and interface data used to forward packets. It addresses the different topic Network forwarding planes RIB versus FIB, not the directly tested PIM sparse mode RP shared tree and shortest path transition failure in the stated incident (A regional site can reach multicast source addresses by unicast but its IPTV stream never starts because the PIM-SM RP mapping is inconsistent.).

This option proposes: Inspect PIM-DM neighbor state, source-specific multicast entries, prune interfaces and receiver interest across the branches. It addresses the different topic PIM dense mode flooding and prune mechanisms, not the directly tested PIM sparse mode RP shared tree and shortest path transition failure in the stated incident (A regional site can reach multicast source addresses by unicast but its IPTV stream never starts because the PIM-SM RP mapping is inconsistent.).

This option proposes: Review VLAN IGMP query source, version, group reports, membership timers and the downstream interface in multicast routing state. It addresses the different topic IGMP querier membership reports and group timeout, not the directly tested PIM sparse mode RP shared tree and shortest path transition failure in the stated incident (A regional site can reach multicast source addresses by unicast but its IPTV stream never starts because the PIM-SM RP mapping is inconsistent.).

This option proposes: Inspect candidate routes' neighboring AS, MED values, other higher-priority attributes and local comparison configuration. It addresses the different topic BGP MED interpretation between neighboring autonomous systems, not the directly tested PIM sparse mode RP shared tree and shortest path transition failure in the stated incident (A regional site can reach multicast source addresses by unicast but its IPTV stream never starts because the PIM-SM RP mapping is inconsistent.).

That option concerns Multicast reverse path forwarding checks. That follows from the targeted action: Trace PIM-SM receiver joins toward an RP and subsequent shortest-path behavior when investigating delayed or suboptimal multicast.

That option concerns IGMPv3 source-specific selection and SSM. That follows from the targeted action: Trace PIM-SM receiver joins toward an RP and subsequent shortest-path behavior when investigating delayed or suboptimal multicast.

That option concerns RSTP designated root and backup topology selection. That follows from the targeted action: Trace PIM-SM receiver joins toward an RP and subsequent shortest-path behavior when investigating delayed or suboptimal multicast.

This option proposes: Assume PIM-DM always requires a rendezvous point and never initially floods multicast packets to uninterested downstream segments. It addresses the different topic PIM dense mode flooding and prune mechanisms, not the directly tested PIM sparse mode RP shared tree and shortest path transition failure in the stated incident (A regional site can reach multicast source addresses by unicast but its IPTV stream never starts because the PIM-SM RP mapping is inconsistent.).

This option proposes: Add extra VLAN IDs to a WLAN VLAN pool and assume client DHCP service automatically appears on every new VLAN with no gateway or scope work. It addresses the different topic WLAN VLAN pools and DHCP address scopes, not the directly tested PIM sparse mode RP shared tree and shortest path transition failure in the stated incident (A regional site can reach multicast source addresses by unicast but its IPTV stream never starts because the PIM-SM RP mapping is inconsistent.).

This option proposes: Assume a router must forward every packet sent to a multicast group whenever it has a unicast default route, regardless of the packet's incoming interface. It addresses the different topic Multicast reverse path forwarding checks, not the directly tested PIM sparse mode RP shared tree and shortest path transition failure in the stated incident (A regional site can reach multicast source addresses by unicast but its IPTV stream never starts because the PIM-SM RP mapping is inconsistent.).

This option proposes: Diagnose a packet-forwarding discrepancy by separating control-plane routes recorded in the RIB from hardware or software forwarding entries installed in the FIB. It addresses the different topic Network forwarding planes RIB versus FIB, not the directly tested PIM sparse mode RP shared tree and shortest path transition failure in the stated incident (A PIM-SM network initially forwards through a shared tree, then switches to a lower-latency source tree, and analysts need to explain the change in (S,G) state.).

This option proposes: Explain how PIM dense mode initially distributes traffic and then prunes interfaces lacking downstream receivers. It addresses the different topic PIM dense mode flooding and prune mechanisms, not the directly tested PIM sparse mode RP shared tree and shortest path transition failure in the stated incident (A PIM-SM network initially forwards through a shared tree, then switches to a lower-latency source tree, and analysts need to explain the change in (S,G) state.).

This option proposes: Diagnose a multicast drop by checking reverse path forwarding against the packet's source rather than only validating the destination group. It addresses the different topic Multicast reverse path forwarding checks, not the directly tested PIM sparse mode RP shared tree and shortest path transition failure in the stated incident (A PIM-SM network initially forwards through a shared tree, then switches to a lower-latency source tree, and analysts need to explain the change in (S,G) state.).

This option proposes: IGMP reports express receiver interest in multicast groups and a querier maintains group membership state; without appropriate reports or queries a router can age out forwarding toward a segment. It addresses the different topic IGMP querier membership reports and group timeout, not the directly tested PIM sparse mode RP shared tree and shortest path transition failure in the stated incident (A PIM-SM network initially forwards through a shared tree, then switches to a lower-latency source tree, and analysts need to explain the change in (S,G) state.).

This option proposes: LOCAL_PREF is an intra-AS BGP path attribute, with larger values generally preferred at its stage of best-path selection; it is not normally advertised to eBGP neighbors. It addresses the different topic BGP LOCAL_PREF within one autonomous system, not the directly tested PIM sparse mode RP shared tree and shortest path transition failure in the stated incident (A PIM-SM network initially forwards through a shared tree, then switches to a lower-latency source tree, and analysts need to explain the change in (S,G) state.).

This option proposes: IP multicast forwarding commonly uses an RPF check toward the source or rendezvous point to prevent loops, so an otherwise reachable multicast group may fail when packets arrive on an unexpected upstream interface. It addresses the different topic Multicast reverse path forwarding checks, not the directly tested PIM sparse mode RP shared tree and shortest path transition failure in the stated incident (A PIM-SM network initially forwards through a shared tree, then switches to a lower-latency source tree, and analysts need to explain the change in (S,G) state.).

This option proposes: Inspect multicast routing entries, incoming interface, unicast RPF route for the source or RP and packet counters on the observed ingress. It addresses the different topic Multicast reverse path forwarding checks, not the directly tested PIM sparse mode RP shared tree and shortest path transition failure in the stated incident (A PIM-SM network initially forwards through a shared tree, then switches to a lower-latency source tree, and analysts need to explain the change in (S,G) state.).

This option proposes: Inspect PIM-DM neighbor state, source-specific multicast entries, prune interfaces and receiver interest across the branches. It addresses the different topic PIM dense mode flooding and prune mechanisms, not the directly tested PIM sparse mode RP shared tree and shortest path transition failure in the stated incident (A PIM-SM network initially forwards through a shared tree, then switches to a lower-latency source tree, and analysts need to explain the change in (S,G) state.).

This option proposes: Examine the level-1 and level-2 routing tables, leak policy, LSP overload flags and route next hops before modifying metric preferences. It addresses the different topic IS-IS routing leakage and overload bit, not the directly tested PIM sparse mode RP shared tree and shortest path transition failure in the stated incident (A PIM-SM network initially forwards through a shared tree, then switches to a lower-latency source tree, and analysts need to explain the change in (S,G) state.).

That option concerns NSSA type seven translation and default routing. That follows from the targeted Recommended action: Trace PIM-SM receiver joins toward an RP and subsequent shortest-path behavior when investigating delayed or suboptimal multicast.

That option concerns PIM dense mode flooding and prune mechanisms. That follows from the targeted Recommended action: Trace PIM-SM receiver joins toward an RP and subsequent shortest-path behavior when investigating delayed or suboptimal multicast.

That option concerns IGMP querier membership reports and group timeout. That follows from the targeted Recommended action: Trace PIM-SM receiver joins toward an RP and subsequent shortest-path behavior when investigating delayed or suboptimal multicast.

This option proposes: Attempt to configure an OSPF BDR role for IS-IS, assuming the DIS cannot operate until a backup DIS has been selected. It addresses the different topic IS-IS designated intermediate system and pseudonode, not the directly tested PIM sparse mode RP shared tree and shortest path transition failure in the stated incident (A PIM-SM network initially forwards through a shared tree, then switches to a lower-latency source tree, and analysts need to explain the change in (S,G) state.).

This option proposes: Assume PIM-DM always requires a rendezvous point and never initially floods multicast packets to uninterested downstream segments. It addresses the different topic PIM dense mode flooding and prune mechanisms, not the directly tested PIM sparse mode RP shared tree and shortest path transition failure in the stated incident (A PIM-SM network initially forwards through a shared tree, then switches to a lower-latency source tree, and analysts need to explain the change in (S,G) state.).

This option proposes: Assume a router must forward every packet sent to a multicast group whenever it has a unicast default route, regardless of the packet's incoming interface. It addresses the different topic Multicast reverse path forwarding checks, not the directly tested PIM sparse mode RP shared tree and shortest path transition failure in the stated incident (A PIM-SM network initially forwards through a shared tree, then switches to a lower-latency source tree, and analysts need to explain the change in (S,G) state.).