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