Two identical metal blocks each have the same internal energy and temperature TH. Block A has remained in an inert environment, while Block B previously underwent an irreversible process that increased the entropy of the block–surroundings combination by ΔS>0 without changing its internal energy or temperature. Each block is now used separately as the sole hot reservoir for a heat engine that exhausts to a large sink at temperature TC(TC<TH). Which statement correctly compares the maximum work WA obtainable from Block A with the maximum work WB obtainable from Block B?
(a) WA>WB because the larger entropy of Block B lowers its Carnot efficiency (η=1−TC/TH).
(b) WA>WB because the earlier entropy production associated with Block B has already rendered some of its internal energy unavailable for work.
(c) WA=WB because both blocks begin the engine cycle with the same temperature and internal energy.
(d) Neither block can supply useful work because each block is in internal equilibrium at temperature TH.