Which statement is true about IGMP?

Which statement is true about IGMP?

A.
Multicast sources send IGMP messages to their first-hop router, which then generates a PIM join
message that is then sent to the RP.

B.
Multicast receivers send IGMP messages to their first-hop router, which then forwards the IGMP
messages to the RP.

C.
IGMP messages are encapsulated in PIM register messages and sent to the RP.

D.
Multicast receivers send IGMP messages to signal their interest to receive traffic for specific
multicast groups.