曳引机制动器两侧的闸瓦与制动轮的间隙是()

曳引机制动器两侧的闸瓦与制动轮的间隙是()

A.0.5~0.7mm

B.0.2~0.35mm

C.5~7mm

D.≤0.7mm

正确答案是4