A parallel plate capacitor has a uniform electric field ' `` \vec{ E } `` ' in the space between the plates. If the distance between the plates is `` 'd' `` and the area of each plate is ' `` A `` ', the energy stored in the capacitor is : `` \left(\varepsilon_{0}=\right. `` permittivity of free space)
(A) `` \frac{1}{2} \varepsilon_{0} E ^{2} ``
(B) `` \varepsilon_{0} EAd ``
(C) `` \frac{1}{2} \varepsilon_{0} E ^{2} Ad ``
(D) `` \frac{ E ^{2} Ad }{\varepsilon_{0}} ``