What type of current does a capacitor store?

A capacitor stores energy in the form of an electric field, which occurs when a direct current (DC) is applied across its terminals. When a DC voltage is applied to a capacitor, it allows current to flow in one direction while charging to the applied voltage. Once the capacitor is charged, it blocks any further flow of DC current, effectively storing the electrical energy.

On the other hand, a capacitor can also interact with alternating current (AC). In an AC circuit, the voltage across the capacitor continually changes direction and magnitude. The capacitor charges and discharges as the AC voltage oscillates, allowing it to pass varying amounts of current based on the frequency of the AC signal. Therefore, in the context of the choices provided, the correct characterization of the type of current a capacitor is capable of storing is associated with alternating current because it is through AC voltage that a capacitor's reactive properties are typically described.

In essence, a capacitor is primarily used in AC circuits due to its ability to store and release energy in response to fluctuating voltage levels, which is why it is correct to associate it with alternating current in this context.