Engine A outputs 20 J of work for every 100 J of heat removed from a hot reservoir. Engine B outputs 15 J of work for every 60 J of heat removed from…

Engine A outputs 20 J of work for every 100 J of heat removed from a hot reservoir.

Engine B outputs 15 J of work for every 60 J of heat removed from a hot reservoir.

Engine C expels 30 J of heat to its surroundings for every 10 J of work it outputs.

Engine D expels 48 J of heat to its surroundings for every 16 J of work it outputs.

Which engine is the least efficient?