How does a switch respond when it receives a message?

How does a switch respond when it receives a message?

A.
It reads the Layer-5 information and sends the message directly to the intended computer.

B.
It reads the Media Access Control (MAC) address and sends the message directly to the intended computer.

C.
It reads the Layer-5 information and broadcasts the message to all the computers that are connected to the switch.

D.
It reads the Media Access Control (MAC) address and broadcasts the message to all the computers that are connected to the switch.