Which IP address/subnet mask combination should a server administrator use for the LAST usable address on a network with a 199.90.10.32/28?

In a network defined by the IP address 199.90.10.32/28, it's essential to first determine the characteristics of this subnet. The subnet mask /28 translates to 255.255.255.240, indicating that the subnet has 16 total IP addresses (2^4, since there are 4 bits for host addresses). This gives a range of addresses from 199.90.10.32 to 199.90.10.47.

The first address (199.90.10.32) is reserved as the network address, and the last address (199.90.10.47) is reserved as the broadcast address. Therefore, the usable IP addresses in this subnet are from 199.90.10.33 to 199.90.10.46.

The last usable IP address in this case is 199.90.10.46. The option that includes the address 199.90.10.47 indicates a broadcast address rather than a usable one, while the other options do not correctly utilize the subnet characteristics.

Since the correct last usable address for the subnet 199.90.10.32/28 is 199.90.10.46 with a subnet