Internal energy is independent of the __________ for an ideal gas.

ANS:C - both (a) & (b)

For an ideal gas, the internal energy depends solely on the temperature. This is a consequence of the ideal gas law, which states that the internal energy of an ideal gas is solely a function of its temperature. So, the correct answer is "neither (a) nor (b)". Internal energy is independent of both pressure and volume for an ideal gas.