a) Capacity, Rotational speed only
b) Rotational speed only
c) Pump, Rotational speed only
d) Capacity, rotational speed and pump

Answer: d
Explanation: Capacity, rotational speed and pump are the factors to be considered for designing a centrifugal pump. The capacity of the pump varies with its rotational speed, the pressure developed by pump varies as the square of the rotational speed and power required by pump varies as the cube of the rotational speed. These relationships are called as Fans Laws.