Which is a correct statement about the subnet mask?

A. The subnet mask is used by the host to determine the destination network.
B. The subnet mask is used in routing to determine the destination network.
C. The router uses its subnet mask when routing a packet.
D. The destination computer checks the subnet mask on the packet to verify that it’s intended for that computer.

A. The subnet mask is used by the host to determine the immediate network and the destination network. It then decides to either route the packet or try to deliver itself without the router’s help.