You are working in a data center environment and are assigned the address range
10.188.31.0/23. You are asked to develop an IP addressing plan to allow the maximum
number of subnets with as many as 30 hosts each. Which IP address range meets these
requirements?

A.
10.188.31.0/26

B.
10.188.31.0/25

C.
10.188.31.0/28

D.
10.188.31.0/27

E.
10.188.31.0/29

Explanation:
Each subnet has 30 hosts < 32 = 25 so we need a subnet mask which has at least 5 bit 0s –
> /27. Also the question requires the maximum number of subnets (which minimum the
number of hosts-per-subnet) so /27 is the best choice.