Which of the following is classified as a scalar quantity?

A scalar quantity is defined as a quantity that has only magnitude, without any direction. Distance is classified as a scalar quantity because it only measures how much ground an object has covered during motion, irrespective of the direction of that movement. For example, if you walk 5 kilometers, that distance does not provide any information about which direction you walked.

In contrast, other options involve direction as well as magnitude. Displacement takes into account the shortest path from the initial to the final position, which incorporates direction. Velocity is a vector quantity that describes the rate of change of displacement over time, including direction. Similarly, acceleration indicates how the velocity of an object changes, and it also has direction associated with it.

Therefore, among the given choices, distance is the only one that fits the definition of a scalar quantity, being purely dependent on the amount covered without any directional component.