Using "stroboscopic photography", you can record the different positions of an object at the same time. The picture shows a stroboscopic photo of two balls A and B when they are in motion.

As can be seen from the picture, the objects in picture A travel the same distance in equal time, so what picture A shows is uniform motion; and in picture B, the distance of the small ball in equal time Different, so ball B moves at a variable speed;

So the answer is: B; In equal time, compare the distance traveled.