Which statement about the scenario represented in the table is true? Assume time is the independent variable.

The distance run is a nonlinear function because it does not have a constant rate of change.
The elevation is a nonlinear function because it does not have a constant rate of change.
Both the distance run and the elevation are nonlinear functions because they do not have constant rates of change.
Both the distance run and the elevation are linear functions because they have a constant rate of change.