What type of current flows in one direction only?

The type of current that flows in one direction only is Direct Current (DC). In a DC circuit, the electric charge maintains a steady flow in a singular, unidirectional manner, which means that the polarity remains constant over time. This consistent flow is crucial for certain applications, such as battery-operated devices, where a stable voltage is needed for reliable performance.

In contrast, Alternating Current (AC) changes direction periodically, which can make it suitable for various applications, particularly in power distribution systems. Pulsating Current, on the other hand, refers to currents that are not smooth like DC but do not alternate polarity like AC, typically occurring in specific circuits or under certain conditions. Therefore, the defining characteristic of Direct Current as flowing in only one direction is what makes it the correct answer to the question.