You need to subnet a network that has 5 subnets, each with at least 16 hosts. Which classful subnet mask would you use?

Answer: Option B

You need 5 subnets, each with at least 16 hosts. The mask 255.255.255.240 provides 16 subnets with 14 hosts-this will not work. The mask 255.255.255.224 provides 8 subnets, each with 30 hosts. This is the best answer.