Which technology is an example of the need for a designer to clearly define features and desired performance when designing advanced WAN services with a service provider?

Which technology is an example of the need for a designer to clearly define features and desired performance when designing advanced WAN services with a service provider?

A.
FHRP to remote branches.

B.
Layer 3 MPLS VPNs secure routing

C.
Control protocols (for example Spanning Tree Protocol) for a Layer 3 MPLS service.

D.
Intrusion prevention, QoS, and stateful firewall support network wide.

Explanation: