What statement is true concerning carbon deposit formation on reciprocating compressor cylinder valves?

Correct Answer: Option A — The rate of carbon deposit formation is directly proportional to the extent of cylinder oil pumping and directly proportional to the cylinder compression temperatures.

Carbon deposits form when lubricating oil oxidizes at high temperatures. Excessive oil pumping provides more fuel for these deposits, while higher compression temperatures accelerate the oxidation process. Both factors are directly proportional to the rate of carbon accumulation on valves, which can lead to overheating and failure.