Which of the following is true about WRED?

A.
WRED cannot be applied to the same interface as CQ, PQ, and WFQ.

B.
WRED drops packets from all flows.

C.
WRED cannot mark with a probability denominator.

D.
WRED cannot be applied to the voice queue.

Explanation:
http://www.cisco.com/en/US/docs/ios/qos/configuration/guide/config_wred.html