A.Voice VLANs are only used when connecting an IP phone and a host to distinct switch ports
B.Access ports that are configured with voice VLANs will always trust the CoS that is received from IP phones
C.Access ports that are configured with voice VLANs may or may not override the CoS value that is received from an IP phone
D.Voice VLANs are configured using the switchport voice vlan vlan-ID interface configuration command
E.Voice VLANs provide a trunking interface between an IP phone and an access port on a switch to allow traffic from multiple devices that are connected to the port
F.Enabling Voice VLAN on a switch port will automatically configure the port to trust the incoming CoS markings

A.probe request/response， authentication request/response， association request/response
B.association request/response， authentication request/response， probe request/response
C.probe request/response， association request/response， authentication request/response
D.association request/response， probe request/response， authentication request/response