Capacitance measures the ability of a circuit to store what?

Capacitance is fundamentally defined as the ability of a circuit to store electric charge. It refers to the capacity of a capacitor, which is a component specifically designed to hold electric charge. When a capacitor is connected to a voltage source, it accumulates charge on its plates, resulting in a potential difference across its terminals. The greater the capacitance of a capacitor, the more charge it can store for a given voltage.

In this context, the other choices do not accurately represent what capacitance measures. Voltage is the potential difference that drives the flow of current, while current refers to the flow of electric charge in a circuit. Energy can be derived from charge and voltage in a capacitor, but capacitance itself specifically pertains to the ability to store charges, not the energy or current directly. Thus, the correct understanding centers around the relationship between capacitance and the storage of electric charges.