Two identical cylinders containing 1 kg of a monatomic ideal gas are heated. In Case 1, as heat is added, the piston moves upward without resistance. In Case 2 the piston is nailed firmly in place and doesn't budge as heat is added. In which case will it take more heat to raise the temperature by 1 degree?

A. Case 1
B. Case 2
C. Need more information.