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 ports