Which statement best explains whether the following graph represents a linear or nonlinear function?

coordinate plane with a graph that passes through the points negative 3 comma 0 and negative 1 comma 4 and 1 comma 4 and 3 comma 0

The graph represents a nonlinear function because there is a constant rate of change.
The graph represents a nonlinear function because the rate of change is not constant.
The graph represents a linear function because there is a constant rate of change.
The graph represents a linear function because the rate of change is not constant.

The graph represents a linear function because there is a constant rate of change.