Which delivery pressure causes the fueling side of the 302AF fueling and defueling valve to close when adjusting the loading pressure relief control counterclockwise?

The correct answer is based on the specific operational characteristics of the 302AF fueling and defueling valve. When adjusting the loading pressure relief control counterclockwise, the valve is designed to close the fueling side when the delivery pressure reaches a threshold that ensures safety and prevents potential over-pressurization in the system.

Setting the adjustment to 5 psi above normal operating pressure (NOP) strikes a balance that allows the system to function effectively while providing an adequate safety margin. This threshold ensures that the fueling and defueling operations can continue smoothly without the risk of pressure imbalances, which could lead to excessive flow or potential damage to the fuel system components.

This understanding highlights why this particular pressure setting is key for the safe and efficient operation of the valve during fueling and defueling processes. The other options represent different pressures that either do not align with the specifications for safe valve operation or exceed the necessary limits, thereby potentially introducing risks to the system's integrity during operation.