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.