Which two multicast protocol statements are true?（）

A、Sparse mode multicast uses a pull model to send multicast traffic to where it is requested

B、Dense mode multicast uses a push model to flood traffic throughout the network and then prunes the unwanted traffic

C、Dense mode multicast requires explicit join messa ges from their members

D、Sparse mode uses reverse path forwarding (RPF) to prune off redundant flows

E、The primary use of sparse mode multicast is for test labs and router performance testing