轮对踏面剥离长度规定：一处不大于mm，两处不大于mm时未达修理值（）

A.① 50 mm

B.② 40 mm

C.③ 30 mm

D.④20mm

A.10

B.20

C.30

D.40

A.25mm

B.30 mm

C.35 mm

D.40 mm

A.20 mm

B.40 mm

C.50 mm

D.22 mm

A.20

B.15

C.10

A.15

B.10

C.20

D.30