Stroboscope photography is a commonly used method when studying the movement of objects. The following picture ABCD is shot separately (once every 0.1s) by a stroboscopic camera (shot every 0.1s).

A. The trajectory is a curve, not a straight line, which is wrong;

B. The trajectory is a straight line, the speed gradually becomes smaller, and the movement is decelerating, which is wrong;

C , The trajectory is a straight line, the speed gradually increases, and the movement accelerates, wrong;

D. The trajectory is a straight line, the distance traveled is the same in equal time, the speed remains unchanged, it is a uniform linear motion, correct.

So choose D.