Which description of the RPF check in the multicast forwarding traffic is true?

RPF (Reverse Path Forwarding) looks up the source IP address of the incoming multicast packet in the unicast routing table to determine which interface leads back to that source. If the packet arrived on that same interface (the RPF interface), the check passes and the packet is forwarded downstream. This mechanism prevents multicast routing loops by ensuring packets travel the correct path.

RPF does not query the BGP database directly - it checks the unicast routing table, which may have routes learned via BGP but the lookup target is the routing table, not the BGP RIB.

RPF checks the source address of the multicast packet, not the destination - multicast destination addresses are group addresses and play no role in the RPF check.

Choice D also starts with source address lookup in the unicast routing table but incorrectly describes the forwarding condition or outcome of the RPF check, making A the accurate and complete description.