问题：

[多选] Which two multicast protocol statements are true？ （Choose two.）  （）

A .  Dense mode multicast requires explicit join messages from their members.
B .  Dense mode multicast uses a push model to flood traffic throughout the network and then prunes the  unwanted traffic.
C .  Sparse mode multicast uses a pull model to send multicast traffic to where it is requested.  
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.