An alternating current (AC) cycle is defined as:

• A. A complete AC cycle includes current flowing in one direction, reversing, and flowing in the opposite direction.
• B. AC cycles involve a constant current in one direction.
• C. AC cycles convert directly from DC to AC.
• D. An AC cycle is the same as a single half-cycle.

Answer: (A)

An AC cycle is the full back-and-forth swing of current or voltage. It starts flowing in one direction, reverses, and then flows in the opposite direction back to the starting point. That complete pattern is what repeats over and over, at a rate set by the frequency.

So the statement describing a complete AC cycle as current flowing in one direction, reversing, and flowing in the opposite direction matches this idea perfectly. In contrast, constant current in one direction describes DC, and converting DC to AC is about how you create AC from DC, not what defines a cycle. A single half-cycle is only half of the full pattern, not the entire cycle.