What is the purpose of the WLC Controller->Multicast->IGMP Timeout feature operating on v5.2?（）

• A、to determine if there are more clients that are using the multicast stream
• B、to limit the time that a client has to request an IGMP join to the controller multicast group
• C、to determine if the multicast router is still alive and responding to multicast clients
• D、to remove clients from the multicast group if the multicast traffic exceeds the allotted bandwidth allowed  for multicast clients