An engineer must automatically copy the IP Prec/DiffServ PHB marking to the EXP bits of the imposed MPLS label on the ingress PE, as well as the MPLS EXP bits to the IP Prec/DiffServ of the egress PE. Which MPLS QoS model is suitable for this requirement?

A.	pipe model
B.	short-pipe model
C.	uniform model
D.	uniform pipe model