The Carnot cycle is the most efficient heat engine cycle because:
(a) the entropy of the working fluid (gas) never changes.
(b) it’s the only heat cycle for which energy is conserved.
(c) there is no waste heat emitted during a Carnot cycle.
(d) the work done by the working fluid during a Carnot cycle equals the heat input during
(e) the entropy of the universe (working gas and external environment) doesn’t change during
any step of the Carnot cycle.