Only then ________how much damage had been caused.

A．she realized

B．she had realized

C．had she realized

D．did she realize

某桩基础桩径0.6m，桩距1.8m，桩位布置如图所示。采用阶梯形承台，下台阶边长6.4m，厚1.2m，上台阶边长3.4m，厚1.0m；桩侧面土水平抗力系数的比例系数，n＝20MN/m⁴，承台侧面土水平抗力系数的比例系数m＝10MN/m⁴，承台底与地基土间的摩擦系数μ＝0.3，承台地基土分担竖向荷载P_c＝1200kN。单桩。ah＞4.0，其单桩水平承载力设计值R_h＝150kN，承台允许水平位移x_0a＝6mm，则复合桩基水平承载力设计值R_h1为（）。

A．234kN

B．336kN

C．350kN

D．3024kN