Which of the following subnet addresses will be the MOST efficient for this network?

A server administrator needs to configure a server on a network that will have no more than 30 available IP addresses .

Which of the following subnet addresses will be the MOST efficient for this network?
A . 255.255.255.0
B . 255.255.255.128
C . 255.255.255.224
D . 255.255.255.252

Answer: C