采用簡易計算式,求圖所示復合式接地網的工頻接地電阻。土壤電阻率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