The statement in option D is TRUE.
From the graph, you can see that one eraser cost 50 cent and all the eraser cost the same. Following the graph, you will observe that, when the total cost of the eraser is $3.5 on the vertical axis, the corresponding point on the horizontal axis is 7.
That particular plot on the graph is telling you that when seven erasers are bought, the total cost is $3.5.