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