You need to configure a new Cisco router to be installed in the Company VOIP network. 
Which  three interface commands will configure the switch port to support a connected Cisco phone and  to trust the CoS values received on the port if CDP discovers that a Cisco phone is attached？ （）

A.Classification and markingoccur using 802.1ab QoS bits before reaching the trust boundary.  
B.A device is trusted if it correctly declassifies packets. 
C.A device is trusted if it correctly classifies packets.
D.Network trust boundaries are automatically configured in IOS version 12.3 and later.  
E.The outermost trusted devices represent the trust boundary.
F.For scalability， classification should be done as close to the edge as possible.

A.CDP must be disabled on the switch port to prevent interference between CDP messages and  voice traffic.
B.Port security cannot be configured on a port that is configured for a voice vlan.
C.Static secure MAC addresses should be configured on voice vlan ports to prevent access by  devices other than IP phones.
D.CDP must be enabled on the switch port to allow configuration information to be passed to the  IP phone.
E.Portfast must be enabled on the switch port.
F.802.1x authentication cannot be configured on a port configured for a voice vlan.

A. Trust boundaries are points in the network where Layer 2 CoS markings are converted to Layer  3 DSCP or IP precedence markings.
B. Trust boundaries are a point in the network where QoS functionality begins and ends.
C. Trust boundaries determine whether certain types of traffic can pass.
D. Trust boundaries are a point in the network where decisions about CoS markings on incoming  packets are made.
E. None of the other alternatives apply