In a network that uses a switch, each port of the switch forms a separate
Acollision domain
Bbroadcast domain
Cautonomous system
Dvirtual circuit
Correct answer: A
Explanation
A switch isolates collisions on each of its ports, so every port is its own collision domain, whereas a hub shares one collision domain among all its ports, and all the ports of a switch still belong to one broadcast domain unless VLANs or a router divide it.