Implementing Cisco IP Switched Networks (SWITCH v2-0) (#350)

You are the network administrator in your company. You have executed the following commands on the Fa0/1 interface of a switch named swtA:

Over a period of time, different hosts are connected to the Fa0/1 switch port of swtA. The MAC addresses of the hosts that were connected to the Fa0/1 port and the order in which they connected are as follows:

After a few days, you notice that the Fa0/1 port is in the shutdown state. Which of the following MAC addresses causes the Fa0/1 port to shut down?