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

Rotary gear pumps rely on tight internal clearances to maintain a pressure seal between the suction and discharge sides. As rotor clearances increase due to wear, internal slippage or recirculation of fluid occurs, directly reducing the volumetric efficiency and overall capacity of the pump at a constant speed.