The Figure Represents a Multiple- Flash Photo of Two Balls

Multiple Choice

The figure represents a multiple- flash photo of two balls moving to the right, and shows both balls at several numbered times. In the figure,

A) neither ball is accelerated, and the upper ball is moving fastest.
B) both balls are accelerated, and the lower ball is moving fastest.
C) the lower ball is accelerated, but the upper ball is not accelerated.
D) both balls are accelerated, and the upper ball is moving fastest.
E) neither ball is accelerated, and the lower ball is moving fastest.