A group of students designed an experiment in an ice rink to represent the solar system. The steps of the experiment are listed below.

1. Choose a student to represent the sun. The planets are represented by two tennis balls.
2. Ask the student to hold the tennis balls in each palm and spin on the ice with arms stretched out.
3. Ask the student to draw in the arms after about 10 spins.
4. Observe the student’s arms rotate faster when they are closer to the body.

The experiment most likely demonstrates that

A. Planets exert gravitational force on the sun.
B. The sun exerts gravitational force on the planets.
C. Speed of a planet depends on its distance from the sun.
D. Speed of Earth depends on its distance from other planets.

I’m suspecting C, but I don’t know.