In PIM-SM, how does a receiver learn the position of a source-specific group?(single answer)
A. The source multicasts (S, G) information to all PIM routers.
B. The source registers (S, G) information with the RP, and the RP multicasts all (S, G) information to all PIM routers.
C.The source registers (S, G) information with the RP, and the receiver sends a (*, G) Join message to the RP. This enables the receiver to obtain (S, G) information.
D. The receiver sends a (*, G) Join message to all interfaces. After the messages reach the source that provides multicast data of group G, the source unicasts (S, G) information to the receiver.