Which set of classes correctly identifies the four traffic classes， from highest priority to lowest priority， specified in the 802.11e standard？（）

• A、 gold， silver， bronze， and platinum
• B、 platinum， gold， silver， and bronze
• C、 titanium， gold， silver， and bronze
• D、 voice and video， best effort， background， and scavenger
• E、 voice， video， best effort， and background
• F、 voice， video， best effort， and scavenger