单项选择题
采用简易计算式,求图所示复合式接地网的工频接地电阻。土壤电阻率ρ=100Ω·m。
A.0.79Ω B.0.85Ω C.0.91Ω D.0.97Ω
A.0.77Ω B.0.88Ω C.0.99Ω D.1.1Ω
A.650m B.760m C.870m D.980m