A) technician a says that the pump check valve should hold system pressure for at least five minutes after the pump is shut off.
b) technician b says that a defective check valve could cause long cranking time.
which technician is correct?

Both technicians A and B are correct  

Explanation:

A pump check valve is device that allows the flow of any fluid in only one direction and prevents the flow from the reverse direction.

               When the pump operates, there is pressure that develops inside the pump. Now when the pump is shut down, the pump check valve is able to hold the pump pressure for sometimes until the pressure inside the pump becomes normal.

               When the pump check valve is defective, there is a drop in pressure inside the regulator or the pump. Because of the drop in pressure, it takes long time for the pump to start and hence longer cranking time.

Thus both technician A and technician B is correct.

Hence the answer is ---

Both technicians A and B are correct  

i believe your answer is mountains.