Which three IP multicast group concepts are true?（）

A、If a packet is sent to a multicast group address, the multicast frame contains the source multicast address.

B、A router does not have to be a member of a multicast group to recei ve multicast data.

C、A router must be a member of a multicast group to send to the group.

D、A router does not have to be a member of a multicast group to send to the group.

E、If a packet is sent to a multicast group address, all members of the multic ast group will receive it.

F、A router must be a member of a multicast group to receive multicast data.