The correct answer is B) higher than normal suction pressure. When the suction valves in a refrigeration compressor are leaking, it allows refrigerant to bypass the compressor, resulting in a higher than normal suction pressure. This is because the refrigerant is not being fully compressed and is able to flow back into the suction side of the compressor. The higher suction pressure is an indication that the suction valves are not sealing properly. The other answer choices are incorrect because: A) an increase in compressor noise could have other causes, C) lower suction pressure would indicate a different issue, and D) lower evaporator temperature would not necessarily be an indication of leaking suction valves.