Which two statements are tru e about the rendezvous point (RP) in a multicast network?（）

• A、The multicast sources must register with the RP to form the multicast distribution tree
• B、An RP is required only in networks running Protocol Independent Multicast dense mode ( PIM DM)
• C、The multicast receivers must register with the RP to form the multicast distribution tree
• D、An RP is required only in networks running Protocol Independent Multicast sparse mode (PIM SM)
• E、An RP is required only in networks running Pro tocol Independent Multicast sparse - dense mode (PIM - SDM)
• F、To form the multicast distribution tree, the multicast sources register with and the receivers join the RP