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