Refer to the exhibit:
Each of these four switches has been configured with a hostname, as well as being configured to run RSTP. No other configuration changes have been made. Which three of these show the correct RSTP port roles for the indicated switches and interfaces? (Choose three.)
A.
SwitchA, Fa0/2, designated
B.
SwitchA, Fa0/1, root
C.
SwitchB, Gi0/2, root
D.
SwitchB, Gi0/1, designated
E.
SwitchC, Fa0/2, root
F.
SwitchD, Gi0/2, root
Please refer http://www.9tut.com/ccna-stp-questions for clear explanation