[单选题]
一般施工现场排水沟的横断面和纵向坡度不宜小于()。
A.0.4m×0.4m,0.1%
B.0.5m×0.5m,0.1%
C.0.4m×0.4m,0.2%
D.0.5m×0.5m,0.2%
参考答案与解析: