Which description of a VNTag is true?

A.	A VNTag is inserted between the source MAC address and the 802.1Q field.
B.	The VNTag is used to identify the service level that is granted to a frame.
C.	A VNTag is based on the destination MAC address and the 802.1Q field.
D.	A VNTag requires a Cisco Nexus 1000v Series Switch.