What type of voltage changes magnitude continually and occasionally changes direction?

The correct answer is Alternating Current (AC) because AC voltage is characterized by its ability to change magnitude continually and reverse its direction periodically. This means that the voltage fluctuates both in strength and in the polarity of the electrical flow, which is typically represented as a sinusoidal waveform over time.

In contrast, direct current (DC) provides a constant voltage that does not change in magnitude or direction. Constant voltage refers to a steady, unchanging voltage without fluctuations, which does not meet the criteria of changes in magnitude or direction. Pulsating voltage can refer to a voltage that has variations but typically does not reverse direction as AC does.

Understanding these characteristics of AC helps to distinguish it from other types of voltage, highlighting its unique behavior in electrical systems.