Sliding Motion

A student is developing a model to explain how the distance between two objects affects the potential energy stored in the system. The model is shown below.

The model shows a child standing on the steps of a slide. An arrow pointing up labeled '1' is next to the steps and an arrow pointing down and to the right labeled '2' is above the slope of the slide.

Multiple Choice Question
Which force accounts for the interaction between the two objects in the model?

A.
chemical

B.
elastic

C.
gravitational

D.
magnetic

C. gravitational