The Cloud, as an ISP Network, Is Running on the MPLS

Multiple Choice

The cloud, as an ISP network, is running on the MPLS (multi-protocol label switching) technology.

-Which router(s) need(s) to be MPLS technology-enabled to fast track the packets between the two hosts?

A) All routers
B) R1 and R6 only
C) R2 and R5 only
D) R3 and R4 only
E) R2, R3, R4, and R5 only