单项选择题

疏散楼梯和走道上的阶梯不应采用螺旋楼梯和扇形踏步,但踏步上下两级所形成的平面角不超过10度,且每级离扶手()处的踏步宽度超过()时,可不受此限。

A.0.25m,0.20m
B.0.25m,0.22m
C.0.20m,0.22m