What is the purpose of IGMP in a multicast implementation?（）

• A、it is not used in multicast
• B、it determines the virtual address group for a multicast destination
• C、it dynamically registers individual hosts in a multicast group on a specific LAN
• D、it is used on WAN connections to determine the maximum bandwidth of a connection
• E、it determines whether Bidirectional PIM or PIM sparse mode will be used for a multicast flow