The landscape photographer is _______ the lighting conditions that are present at the time of 

the shoot.

A．at the expense of

B．at the risk of

C．in the way of

D．at the mercy of

有一完全井，半径r₀=0.3m，含水层厚度H=15m，土壤渗透系数k=0.0005m/s，抽水稳定后，井水深h=10m，影响半径R=375m，则由达西定律得出的井的抽水量Q为（）。（其中计算系数为1.366）

A．0.0276m³/s

B．0.0138m³/s

C．0.0414m³/s

D．0.0207m³/s