A network security engineer configured IP multicast in the virtual router to support a new application. Users in different network segments are reporting that they are unable to access the application.
What must be enabled to allow an interface to forward multicast traffic?
To forward multicast traffic on a network, Protocol Independent Multicast (PIM) must be enabled on the interface. PIM is the protocol used for multicast routing that helps in forwarding multicast packets between different networks. While IGMP is used for managing group membership on local segments, it is PIM that handles the delivery of multicast traffic across the network.
You must enable IP multicast for the virtual router, configure Protocol Independent Multicast (PIM) on the ingress and egress interfaces, and configure Internet Group Management Protocol (IGMP) on receiver-facing interfaces. https://docs.paloaltonetworks.com/pan-os/10-1/pan-os-networking-admin/ip-multicast/configure-ip-multicast
The nuance to this question is thus: to 'forward mcast traffic' (actual question) requires PIM, but for a receiver to join a group (different than the actual question) requires IGMP.
D is correct