Correct option is D
In IP Class-A addresses, the first byte is reserved for network IDs.
IP Class-A addresses:
· The network ID is 8 bits long.
· The remaining 24 bits are for the local or host address.
· The first bit of the network address indicates the network class.
· There are 126 possible Class A network addresses.
· The network address 127 is reserved for local loopback addresses.
· A network address of all ones indicates a broadcast address.
· The default subnet mask for class A is 2555.x.x.x.
· The InterNIC assigns only the first byte of a class A number.
· The owner of the network number is responsible for using the remaining three bytes.
