单项选择题

泵房内管道管外底距地面的距离,当管径DN≤150mm时,不应小于();当管径DN≥200mm时,不应小于()。

A.0.20m,0.25m
B.0.30m,0.35m
C.0.20m,0.30m
D.0.15m,0.25m