The correct answer is: A. Electric
A capacitor is an electrical device that stores energy in an electric field. It is made up of two conductive plates separated by an insulating material. When a voltage is applied to the capacitor, an electric field is created between the plates. This electric field stores the energy.
A magnetic field is a region of space where a magnetic force can be detected. It is created by moving electric charges, such as those in a current-carrying wire. A capacitor does not create a magnetic field.
Therefore, the correct answer is A. Electric.