Correct option is A
Self priming pumps overshadow the function of self auxiliary device. A pump that can evacuate air
is called as self priming pumps. In normal conditions, it is difficult for centrifugal pumps to evacuate the air from the inlet line leading to a fluid level to a different altitude. Self-priming pumps maintain their prime automatically without requiring additional devices or manual intervention. Hence, they overshadow the need for a self-auxiliary device that might otherwise be necessary to keep the pump primed.
