When the switch receives a unicast data frame, it will look up the destination MAC address in the MAC table. Which of the following statement is wrong?
A . If the MAC address is found, and the corresponding port of the MAC address in the MAC address table is not the one that enters the switch, the switch performs the forwarding operation.
B . If the MAC address is found, and the corresponding port of the MAC address in the MAC address table is the port that the frame enters the switch, the switch performs the discard operation.
C . If the MAC address is not found, the switch performs the flooding operation.
D . If the MAC address is not found, the switch performs the discard operation.
Answer: D