Refer to the exhibit.

An MPLS-based service provider wants to deploy QoS over its backbone. Original customer QoS
information must be preserved when the packet leaves the MPLS network. In addition, the egress
LSR must forward packets according to the LSP Diff-Service information, as depicted in the
topology. Which QoS model satisfies these requirements?

A.
uniform model

B.
pipe model

C.
short-pipe model

D.
IntServ model