The Cisco AutoQoS feature is being used throughout the Company VOIP network.  Which three  statements about this feature are true？（）

• A、The "mls qos" global configuration command must be entered before configuring AutoQoS.
• B、CEF must be enabled.
• C、The "no auto qos voip" command is used to disable Cisco AutoQos and revoke all  configurations generated by Cisco AutoQos.
• D、CDP must be enabled.
• E、SNMP must be enabled.