Which of the following describes a direct current?

A direct current (DC) is characterized by the continuous flow of electric charge in one direction. This steady and unidirectional movement of electrons distinguishes it from alternating current (AC), where the flow periodically reverses direction. In direct current, the voltage remains constant, providing a stable and dependable power supply for devices that require a consistent and reliable source of energy, such as batteries and DC powered electronics. This stability is what allows DC to be particularly useful in many applications, from small batteries to larger power supplies. The other options do not capture this essential characteristic of direct current, which is the continuous and unchanging direction of flow.