A.Devices connected to interfaces FastEthernet3/1 and FastEthernet3/2 are sending BPDUs with a superior root bridge parameter， but traffic is still forwarded across the ports.
B.Interfaces FastEthernet3/1 and FastEthernet3/2 are candidate for becoming the STP root port， but neither can realize that role until BPDUs with a superior root bridge parameter are no longer received on at least one of the interfaces.
C.Devices connected to interfaces FastEthernet3/1 and FastEthernet3/2 are sending BPDUs with a superior root bridge parameter and no traffic is forwarded across the ports.Once inaccurate BPDUs have been stopped， the interfaces automatically recover and resume normal operation.
D.Devices connected to interfaces FastEthernet3/1 and FastEthernet3/2 are sending BPDUs with a superior root bridge parameter and no traffic is forwarded across the ports.Once inaccurate BPDUs have been stopped， the interfaces will need to be administratively shut down， and brought back up， to resume normal operation.