Which two statements about WRED are true？ （）

• A、WRED can selectively discard lower priority traffic when the interface becomes congested and can provide differentiated performance characteristics for different classes of service.
• B、Resource Reservation Protocol （RSVP） and WRED cannot be configured on the same interface.
• C、WRED will throttle back voice traffic only as a last resort.
• D、If the average queue length is greater than the minimum threshold but less than the maximum threshold， then based on the drop probability， WRED will either queue the packet or perform a random drop.
• E、WRED statistically drops more packets from low-bandwidth users than high-bandwidth users. Therefore， traffic sources that generate the least traffic are more likely to be slowed down than traffic sources that generate the most traffic.
• F、 WRED treats non-IP traffic as precedence 4.