为自己加油

Each main wheel is provided with a hydraulic actuated multidisc brake unit bolted to a flange on the axle. In the above sentence ,"a hydraulic actuated multidisc brake unit" means

A.一个多刹车盘装置;
B.一个液压操纵的刹车盘装置;
C.一个液压操纵的多刹车盘;
D.一个液压操纵的多刹车盘装置;