Regarding the description of IGMP Snooping-working mechanism, which is the correct?

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

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Answer: B