Final answer:
The correct answer is to use a Class C subnet mask for creating 5 subnets with at least 16 hosts each. Class C allows for enough subnets and host addresses while being the most efficient for the requirements specified.
Step-by-step explanation:
The question involves determining the appropriate subnet mask to use when segmenting a network into 5 subnets, each with at least 16 hosts. Using classful subnetting, you would require at least 4 bits for the host portion (to support 16 hosts, as 2^4 = 16 hosts) and likely another bit to ensure enough subnets (as 2^2 only gives us 4 subnets, but 2^3 gives us 8 subnets, which is sufficient for the 5 needed).
Given these requirements, a Class C subnet mask is most appropriate because it starts with a default subnet mask of 255.255.255.0, which supports up to 256 hosts. By borrowing 3 bits for subnets, the new subnet mask becomes 255.255.255.224 (or in binary: 11111111.11111111.11111111.11100000). This supports 8 subnets, each with up to 32 addresses, 30 of which are usable for hosts when you subtract the network and broadcast addresses.Class A and Class B masks would provide more host addresses than needed and are not as efficient for this case. Class D is not used for standard networking, as it is reserved for multicast. Therefore, the correct answer is a Class C subnet mask.If you need to subnet a network with 5 subnets, each requiring at least 16 hosts, you would use a Class C subnet mask. A Class C subnet mask allows for a maximum of 256 hosts per subnet, which is more than enough for our requirement of at least 16 hosts per subnet. The Class C subnet mask is 255.255.255.0.