Which statement is true about IGMP?
A. Multicast source 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 message to signal their interest traffic multicast groups.
C. IGMP message are encapsulated in PIM register message and send to the RP.
D. Multicast receivers send IGMP message to their first-hop router, which then forwards the IGMP message to the RP.
