Which of the following statements about the Reverse Path Forwarding (RPF) mechanism are true? (Choose two.)
A. Multicast RPF does not depend on unicast routing.
B. All multicast protocols adopt the RPF mechanism.
C. A router discards the received multicast packets if the packets fail the RPF check.
D. The RPF mechanism has two functions: 1. It prevents multicast routing loops; 2. It avoids forwarding redundant multicast data packets.