Two cylinders, one containing 1 mole of $\ce{C4H10}$ gas at $\pu{1 atm}$ and the other containing 1 mole of $\ce{CH4}$ gas at $\pu{1 atm}$, are at $\pu{288 K}$. If each gas absorbs $\pu{100 J}$ of heat under conditions of constant volume, which of the following is true?
(a) The temperature of the $\ce{CH4}$ increases more than the temperature of the temperature of the $\ce{C4H10}$.
(b) The internal energy of both the $\ce{CH4}$ and the $\ce{C4H10}$ decreases.
(c) The heat capacity of the $\ce{C4H10}$ is less than the heat capacity of the $\ce{CH4}$
(d) The entropy of both the $\ce{CH4}$ and the $\ce{C4H10}$ decreases.
(e) The heat transferred to the $\ce{C4H10}$ is greater than the heat transferred to the $\ce{CH4}$.
The correct answer is (a). I am trying to eliminate answers, but I seem to get stuck.
We know that (b) is clearly false as we've added heat and no work is done, therefore the internal energy for both gases must increase. Likewise, (d) is false as the entropy should increase as the molecules have more heat and become more disordered. Finally, (e) is incorrect as we transferred $\pu{100 J}$ of heat to both systems.
But here is where I get stuck. I can't seem to eliminate (c) from just the information given.