What is modeled by the graph segment between B and C?

A graph with time on the x-axis and height on the y-axis. The graph increases from point A to point B, is constant between points B and C, increases between points C and D, and then decreases from point D to point E.
The height is remaining constant over time.
The time is remaining constant while the height changes.
The height is increasing.
The height is decreasing.