What benefit does AToM provide to the service provider’s customers?

What benefit does AToM provide to the service provider’s customers?

A.
By supporting Layer 2 VPNs, customers maintain control of their site-to-site routings over the WAN.

B.
By supporting Layer 3 VPNs, a full mesh of virtual circuits will not be required between the different customer sites to enable optimal routing.

C.
By supporting secured Layer 3 VPNs, customers do not have to deal with the complexity of configuring IPSec.

D.
By supporting MPLS traffic engineering over ATM, customers can better utilize their WAN link.

E.
By supporting Diff-Serv QoS, AToM allows customers to deploy voice/video applications across the WAN.