ANS:A - a vector quantity

The velocity of a moving body is: "a vector quantity." Velocity is defined as the rate of change of displacement with respect to time. It is a vector quantity because it has both magnitude and direction. The magnitude of velocity represents the speed of the object, while the direction of velocity indicates the object's direction of motion. Therefore, velocity includes both numerical value (magnitude) and direction, making it a vector quantity. In contrast, scalar quantities have magnitude only, without direction. Examples of scalar quantities include speed, mass, and temperature. Thus, velocity is considered a vector quantity due to its magnitude and direction.