In the implementation of VLSM techniques on a network using a single Class C IP address,which subnet mask is the most efficient for point-to-point serial links?

In the implementation of VLSM techniques on a network using a single Class C IP address,which subnet mask is the most efficient for point-to-point serial links?

A.
255.255.255.240

B.
255.255.255.254

C.
255.255.255.252

D.
255.255.255.0

E.
255.255.255.248