The Internet Group Management Protocol (IGMP) Is a Communications Protocol

The Internet Group Management Protocol (IGMP) is a communications protocol used to manage the membership of Internet Protocol multicast groups. IGMP is used by IP hosts and adjacent multicast routers to establish multicast group memberships .What is the purpose of IGMP in a multicast implementation?

A) it is used in multicast
B) it is not used in multicast
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