The capacity of a gear type rotary pump, when operated at a constant speed, will decrease with an increase in the pump __________.

Correct Answer: Option D — rotor clearances

Gear pumps rely on tight internal clearances between the rotors and the casing to maintain a positive displacement seal. As these clearances increase due to wear, internal slippage rises, allowing fluid to recirculate from the discharge to the suction side, thereby reducing the pump's effective capacity at constant speed.