In PIM-SM what control plane signaling must a multicast source perform before it begins to send multicasttraffic to a group?()
A.The source must send a PIM Register message to the rendezvous point (RP).
B.The source must first join the multicast group using IGMP before sending.
C.The source must perform a Request to Send (RTS) and Clear to Send (CTS) handshake with the PIM designated router (DR).
D.No control plane signaling needs to be performed; the source can simply begin sending on the local subnet.