An ideal engine may be thought of as a device operating in reversible cycles between two heat reservoirs, one at a higher temperature than the other. In each cycle, the engine takes a certain amount of heat from the higher temperature reservoir R1. A fraction of this energy is used by the engine to do work, while the rest of the energy is transferred to the lower temperature reservoir R2.
Which statement pertaining to entropy is true?
A) The entropy of the reservoir R1 increases.
B) The entropy of the reservoir R2 increases.
C) The entropy of the engine increases after each complete cycle.
D) The entropy of the engine decreases after each complete cycle.