Which multicast address is reserved for cisco-rp-discovery?

A.
224.0.1.37

B.
224.0.1.38

C.
224.0.1.39

D.
224.0.1.40

Explanation:
Auto-RP is a mechanism to automate distribution of RP information in a multicast network. The
Auto-RP mechanism operates using two basic components, the candidate RPs and the RP
mapping agents.
Candidate RPs advertise their willingness to be an RP via “RP-announcement” messages. These
messages are periodically sent to a reserved well-known group 224.0.1.39 (CISCO-RPANNOUNCE).
RP mapping agents join group 224.0.1.39 and map the RPs to the associated groups. The RP
mapping agents advertise the authoritative RP-mappings to another well-known group address
224.0.1.40 (CISCORP-DISCOVERY). All PIM routers join 224.0.1.40 and store the RP-mappings
in their private cache.
Figure 2 shows the Auto-RP mechanism where the RP mapping agent periodically multicasts the
RP information that it receives to the Cisco-RP-Discovery group.

http://www.cisco.com/en/US/prod/collateral/iosswrel/ps6537/ps6552/whitepaper_c11-508498.html