On a coordinate plane, a piecewise function has 3 lines. The graph shows cleaning time in hours on the x-axis and total cost in dollars on the y-axis. The first line has an open circle at (0, 50) and continues horizontally to a closed circle at (2, 50). The second line has an open circle at (2, 100) and continues horizontally to a closed circle at (6, 100). The third line has an open circle at (6, 200) and continues horizontally to a closed circle at (8, 200). The graph represents the cleaning costs charged by a housekeeping service. Which statement is true of the cost function?