The correct option is D. The only true statement is the one written at option D, all other options are wrong. From the graph, you can see that one eraser cost 50 cent and two erasers cost one dollar. If you trace the graph, you will notice that on the vertical axis where $3.5 is written, the dot there tallies with figure 7 on the horizontal axis. That is telling you that 7 erasers cost $3.5.
IF you count the dots for each graph, you would see that the minimum for B is Higher than group A's maximum, Therefore, the numbers do not overlap. This means that at a simple glance you can see which company does better.