Energy stored in a parallel capacitor is 12 qv, where q =cv so 1/2 cv2.

A suggests that the energy stored in a parallel plate capacitor is given by CV. However, this option is incorrect. The expression CV corresponds to the charge stored in the capacitor, not its energy. The energy stored in a capacitor depends on the voltage across its plates.

B suggests that the energy stored in a parallel plate capacitor is given by CV2. However, this option is also incorrect. The correct expression for the energy stored in a parallel-plate capacitor does not involve squaring the voltage.

C suggests that the energy stored in a parallel plate capacitor is given by 1/2 CV. Although this expression is similar to the correct expression, it is not accurate. The correct expression for the energy stored in a parallel plate capacitor does involve a factor of 1/2, but it is not placed in front of CV.

The energy stored in a parallel plate capacitor is given by the formula:

E = 1/2 * C * V2

Where:

E is the energy stored in the capacitor.

C is the capacitance of the capacitor, and

V is the voltage across the capacitor.

This formula represents the relationship between the capacitance, voltage, and energy stored in a capacitor. It shows that the energy stored in the capacitor is directly proportional to the square of the voltage and the capacitance. The factor of 1/2 in the formula arises from the integration of the voltage with respect to charge during the charging process of the capacitor.