IPSec-based site-to-site VPNs is better than traditional WAN networks in what?

IPSec-based site-to-site VPNs is better than traditional WAN networks in what?

A.
Delay guarantees, span, performance, security and low cost

B.
Bandwidth guarantees, support for non-IP protocols, scalability and modular design guidelines

C.
Bandwidth guarantees, flexibility, security and low cost

D.
Span, flexibility, security and low cost