In a thermodynamic process, helium gas obeys the law, T P⁻²/⁵ = constant. The heat is given to n moles of He in order to raise the temperature from T to 2T is:

As the helium gas obeys TP⁻²/⁵ = constant which is a characteristic of the adiabatic reversible process, the process is an adiabatic reversible process for which q = 0. Hence, option C is correct.