What could be the cause of this problem?

The following commands have been configured under the fa0/1 interface on the 2950 switch:

wrr-queue bandwidth 20 1 80 0
mls qos trust cos
mls qos trust device cisco-phone

Voice traffic from the IP phone that is directly connected to the fa0/1 interface is experiencing excessive delays.

What could be the cause of this problem?

A.
The wrr-queue bandwidth weightings are not correct.

B.
The default wrr-queue cos-map is being used.

C.
The default cos-to-dscp map is being used.

D.
The default dscp-to-cos map is being used.

E.
The trust boundary configuration is not correct.

Explanation:

Use the wrr-queue bandwidth global configuration command to assign weighted round robin (WRR) weights to the four class of service (CoS) priority queues. Use the no form of this command to disable the WRR scheduler and enable the strict priority scheduler.

wrr-queue bandwidth weight1…weight4
no wrr-queue bandwidth

Use the show wrr-queue bandwidth user EXEC command to display the weighted round-robin (WRR) bandwidth allocation for the four class of service (CoS) priority queues.