When the link type of the ONU port is Access , its processing method for the upstream message is ____ .

When the link type of the ONU port is Access , its processing method for the upstream message is ____ .
A . only allowed without belt tag packets through, and packets add the default VLAN ‘s tag
B . Only the packets with the default VLAN tag are allowed to pass and go to the tag
C . for without receipt of the Tag message, add the default VLAN tag , to receive with tag packets forwarded directly
D . only allowed with a tag messages by

Answer: A