单项选择题

地下水分布着三层土,厚度均为1米,渗透系数分别为K1=1m/d,K2=2m/d,K3=10m/d。求土层的水平等效渗透系数Kx和垂直等效渗透系数Ky()。

A.Kx=1.87m/d;Ky=4.33m/d
B.Kx=1.87m/d;Ky=1.87m/d
C.Kx=4.33m/d;Ky=4.33m/d
D.Kx=4.33m/d;Ky=1.87m/d