表面粗糙度Ra的基本系列为0.012,0.025,0.050,0.100,0.200.....，单位为um,它们属于哪个系列？

表面粗糙度Ra的基本系列为0.012,0.025,0.050,0.100,0.200.....，单位为um,它们属于哪个系列？
A.R10/3
B.R5
C.R10
D.R20
正确答案：R10/3