What type of acceleration indicates a change in speed and direction simultaneously?

Angular acceleration signifies a change in speed and direction simultaneously because it describes the rate of change of angular velocity over time. When an object is moving in a circular path, its direction is constantly changing, even if the speed remains constant. This change in direction, coupled with any change in speed, is what angular acceleration encompasses.

In contrast, linear acceleration refers to a change in the speed of an object moving in a straight line and does not account for directional changes. Transverse acceleration pertains specifically to changes in the direction of an object moving along a curved path, but it's a component of angular motion rather than the full concept required by the question. Radial acceleration deals with the change in direction towards the center of a circular path but does not address changes in speed. Thus, angular acceleration is the most comprehensive choice that involves both changing speed and a change in the direction of motion.