The diagram illustrates how the speed of a falling object varies over time. Which row describes the object's motion from X to Y, and from Y to Z?
- Abetween X and Y: accelerating; between Y and Z: at rest
- Bbetween X and Y: accelerating; between Y and Z: constant speed
- Cbetween X and Y: decelerating; between Y and Z: at rest
- Dbetween X and Y: decelerating; between Y and Z: constant speed