—Mary was being badly treated when John happened to pass by and helped her out.

—I think it was not a pure ________but had been well planned.

A．coincidence

B．consequence

C．incident

D．chance

正值农忙季节，农田需要大量的灌溉用水，若水泵在0.5h内把360m³的水抽到5m高处（g取10N/kg），则水泵对水做功的功率至少为（　　）

A．1.8×10⁶J

B．3.6×10⁶W

C．10kW

D．3.6×10⁷W