Which of the following best describes direct current (DC)?

Direct current (DC) refers to the flow of electric charge in a single direction, consistently maintaining that flow without reversing. This characteristic is fundamental to DC, as it is used in many electronic devices and batteries, where stable and predictable voltage is necessary for operation.

In contrast to other forms of current, particularly alternating current (AC), DC does not switch directions periodically. The consistency of direction in DC makes it particularly suitable for applications where steady voltage is required, such as in powering circuits and devices like smartphones, laptops, and electric vehicles.

While aspects like fluctuating voltage levels generally apply to alternating current, direct current typically maintains a constant voltage. Moreover, the ability to store electric charge, such as in batteries, is a defining feature of both DC and certain methods of energy storage, so the notion that DC cannot be stored doesn't apply correctly when understood in context. Therefore, the defining characteristic of DC as a steady, unidirectional flow of electricity supports the assertion that it flows in one direction consistently.