The ip pim autorp listener command is used to do which of these?

A.
Enable a Cisco router to “passively” listen to Auto-RP packets without the router actively
sending or forwarding any of the packets

B.
Allow Auto-RP packets in groups 224.0.1.39 and 224.0.1.40 to be flooded in dense mode out
interfaces configured with the ip pim sparse-mode command

C.
Enable the use of Auto-RP on a router

D.
Configure the router as an Auto-RP mapping agent

Explanation:
The IP Pim autorp listener allows the Group 224.0.0.39 & 224.0.0.40 to be dense flooded. As the
RP announces 224.0.0.39 to the mapping agent and the mapping agent announces 224.0.0.40 to
all routers part of the group. where it can be applied:
It can be applied when dense mode is not configured, for example if you have Sparse-mode
Multicast Network, and you need not to statically define your RP or use Autorp.