(iii) An electric field $E$ is established between the plates of an air filled parallel plate capacitor, with charges $Q$ and $-Q$. $V$ is the volume of the space enclosed between the plates. The energy stored in the capacitor is : (A) $\frac{1}{2} \varepsilon_0 E^2$ (B) $\varepsilon_0 Q^2 E$ (C) $\frac{1}{2} \varepsilon_0 E^2 V$ (D) $\varepsilon_0 E Q V$