In PowerPoint, the Animation Scheme feature is used to apply motion effects to different objects on a slide. It allows you to add animations to text, images, shapes, and other elements to make them appear, disappear, or move in a specific way during a presentation.
While (A) Slide Transition refers to effects applied when moving from one slide to another, and (B) Slide Design relates to the overall look and layout of the slide, (C) Animation Objects is not a standard term in PowerPoint. Therefore, (D) Animation Scheme is the most appropriate choice for applying motion effects to objects on a slide.