Which two statements about the implementation of WLAN QoS are true？（）

• A、The 802.11e standard is the IEEE 802.11 OoS WLAN standard.
• B、The Wi-Fi Multimedia （WMM） standard decreases the eight priority levels to four access categories.
• C、The Wi-Fi Multimedia （WMM） standard is a Wi-Fi Alliance standard that increases the four priority levels to eight access categories.
• D、The Wi-Fi Multimedia （WMM） standard is an IEEE standard that increases the four priority levels to eight access categories.
• E、Wireless 802.11 deploys Distributed Coordination Function （DCF）， carrier sense multiple access with collision detection （CSMA/CD）， interframe spacing， and random wait timers to avoid collisions.
• F、Wireless OoS designs and implementations commonly use Layer 3 differentiated services code point （DSCP） or Layer 2 802.1 p to ensure priority