Answer: Step function (or staircase function)
This is because the graph resembles steps or a staircase.
Each step is a horizontal line as described by the pricing chart.
- From x = 0 to x = 25, we'll have a horizontal line y = 3.50
- From x = 25.01 to x = 75, we have a horizontal line y = 5.95
- From x = 75.01 to x = 125, we have a horizontal line y = 7.95
- From x = 125.01 and onward, we have a horizontal line y = 9.95
The diagram below shows this. Note how the horizontal lines are separate pieces that are not connected by vertical lines. Vertical lines are not allowed in functions.