Which of the following distance-time graph (x - t) represents one-dimensinal uniform motion?

Uniform motion implies that an object moves with a constant speed, covering equal distances in equal intervals of time. On a distance-time graph (x-t), the slope of the line represents the speed of the object. Therefore, uniform motion is represented by a straight line with a constant, non-zero slope (inclined to the time axis). Curved lines represent accelerated (non-uniform) motion, and a horizontal line represents an object at rest.