单项选择题
A. Configure a class map that sets the DE bit so that the policy map can correctly apply a violate-action if the policy is exceeded.
B. Configure a service policy that sets the DE bit and apply it to the serial interface connected to the Frame Relay WAN.
C. Configure a policy map that has a burst-max action of setting the DE bit if the policy is exceeded.
D. Configure a policy map that has a violate-action to change the DE bit from 0 to 1.