Which of the following characteristics describe the Root Guard feature？（Choose all that apply.）（）

A. The port must be put into forwarding state manually after root-inconsistent state has beencorrected
B. A Root Guard port receiving superior BPDU goes into a root-inconsistent state
C. A Root Guard port receiving inferior BPDU goes into a root-inconsistent state
D. While the port is in a root-inconsistent state no user data is sent across that port
E. The port returns to a forwarding state if inferior BPDUs stop
F. It should be applied to all switch port