Which two statements about packet marking at the data link layer are true? (Choose two)

Which two statements about packet marking at the data link layer are true? (Choose two)

A.
Through the use of DE markings, Frame Relay QoS supports up to 10 classes of service.

B.
Frames maintain their class of service (CoS) markings when transitin a non-802.1p link.

C.
IEEE 802.1p supports up to 10 class of service (CoS) markings.

D.
In an 802.1q frame, the 3-bit 802.1p priority field is used to identify the class of service (CoS) priority.

E.
The 802.1p CoS markings are preserved through the LAN, but are not maintained end to end.