About the description of IGMP Snooping working mechanism, which of the following statement is true?

About the description of IGMP Snooping working mechanism, which of the following statement is true?
A . The Layer 2 switch establishes and maintains the PIM routing table at Layer 2 by continuously monitoring IGMP messages
B . When IGMP Snooping is not running, multicast messages will be broadcast on the layer 2. After IGMP Snooping is running, the messages will no longer be broadcast on the layer 2, but will be multicast on the layer 2.
C . If the host sends an IGMP leave message, the switch will add the host to the corresponding multicast table
D . If a host sends an IGMP host report message, the switch will delete the multicast entry corresponding to the host

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Answer: B