a
In a process $P V^{x}=$ constant, molar heat capacity is given by $C=\frac{R}{\gamma+1}+\frac{R}{1-x}$
As the process is $\frac{P}{V}=$ constant
i.e., $P V^{-1}=$ constant, therefore, $x=-1$
For an ideal monatomic gas, $\gamma=\frac{5}{3}$
$\therefore C=\frac{R}{\frac{5}{3}-1}+\frac{R}{1-(-1)}=\frac{3}{2} R+\frac{R}{2}=2 R$
$\Delta Q=n C(\Delta T)=1(2 R)\left(2 T_{0}-T_{0}\right)=2 R T_{0}$