For the irreversible reaction, Ca+ 2C = Ca C2, Δ H°298 = - 60000 J . mole-1. If a system initially containing 2 moles of calcium, 3 moles of carbon and 1 mole of calcium carbide is allowed to react to completion, the heat evolved at 298 K will be
(A) 30,000 J
(B) 60,000 J
(C) 90,000 J
(D) 2,40,000 J
(A) 30,000 J
(B) 60,000 J
(C) 90,000 J
(D) 2,40,000 J