问题：

[单选] 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.