You are correct, the answer is A) rising and falling with each stroke. When testing a reciprocating refrigeration compressor for leaking discharge valves, stopping the compressor and turning the discharge service valve all the way in allows you to manually turn the compressor over. If the discharge valves are leaking, the pressures on the compound gauge will rise and fall with each manual stroke of the compressor. This is because the leaking discharge valves are allowing refrigerant to flow back and forth between the discharge and cylinder, rather than being properly sealed. The other options are incorrect because: B) a vacuum would indicate the discharge valves are not leaking, C) increasing pressures would indicate a different issue, and D) decreasing pressures do not match the expected behavior of a leaking discharge valve.