Apart from interdomain multicast routing, what else is MSDP used for?

A.
Source Specific Multicast and IGMPv2

B.
Announcing multicast sources to BGP speakers

C.
Anycast RP

D.
Intradomain multicast routing

Explanation:
http://www.cisco.com/en/US/docs/ios/12_2/ip/configuration/guide/1cfmsdp_ps1835_TSD_Product
s_Configuration_Guide_Chapter.html