Final answer:
B) Low-pressure cutout. A valve that prevents an evaporator's pressure from dropping below a set limit is often known as a low-pressure cutout.
Step-by-step explanation:
A valve that prevents an evaporator's pressure from dropping below a set limit is often known as a low-pressure cutout. It is designed to maintain safe operating pressure levels in the evaporator. This valve opens and closes based on the pressure readings and helps regulate the flow of the refrigerant.