A coil of resistance $R$ connected to an external battery is placed inside an adiabatic cylinder fitted with a frictionless piston and containing an ideal gas. A current $I=a_{0} t$ flows through the coil $\left(a_{0}\right.$ is a teve constant). For time interval $t=0$ to $t=t_{0}$, the piston goes up to a height of $($ Assume $\Delta \mathrm{U}=0)$
(A) $\frac{a_{0}^{2} R^{2} t_{0}^{2}}{2 m g}$
(B) $\frac{a_{0}^{2} R t_{0}^{3}}{2 m g}$
(C) $\frac{a_{0}^{2} R t_{0}^{3}}{3 m g}$
(D) $\frac{a_{0}^{2} R t_{0}^{2}}{3 m g}$