单项选择题
A.YMLU4456789(1) B.YMLU4456789*2(40) C.TOLU4028987*2(40) D.YMLU4456789/20/自重
A.380 B.350 C.1000 D.500
A.3‰ B.3/1 C.0.3/1 D.502/0.3/1