Which three IP multicast group concepts are true？ （Choose three.） （）

A.If a packet is sent to a multicast group address， all members of the multicast group will receive it

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

C.A router does not have to be a member of a multicast group to receive multicast data.

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

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

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