In the following exhibit, which switch interface will become a non-designated port?

A. Switch A Fa0/0
B. Switch A Fa0/1
C. Switch C Fa0/4
D. Switch C Fa0/5

D. Switch B is the root port, therefore Switch A Fa0/0 and Switch C Fa0/4 are root ports. Between Switch A Fa0/1 and Switch C Fa0/5, one of the ports needs to be blocking. Since Switch C Fa0/5 has the highest MAC address, its port is put into a blocking state.