Which subnet mask provides the most efficient use of a Class C address space for a company that requires 10 subnets and 12 hosts per subnet?

Which subnet mask provides the most efficient use of a Class C address space for a company that
requires 10 subnets and 12 hosts per subnet?

A.
255.255.255.192

B.
255.255.255.248

C.
255.255.255.0

D.
255.255.255.224

E.
255.255.255.252

F.
255.255.255.240

Explanation: