Choose two commands that are required to enable multicast on a router， when it is known that thereceivers use a specific functionality of IGMPv3.（）

A.MD5
B.There is no Type 0 authentication
C.SHA1
D.Null

A.UDP/1812
B.UDP/1813
C.TCP/1812
D.TCP/1813

A.The MPLS header is 2 bytes，and the EXP field is 3 bits long.
B.The MPLS header is 1 byte，and the EXP field is 3 bits long.
C.The MPLS header is 4 bytes，and the EXP field is 3 bits long.
D.The MPLS header is 3 bytes，and the EXP field is 3 bits long.