Can someone explain this question? thank you

17. In producing a budget constraint line for combinations of staples and paper clips which are sold by the box, a student labels the points (0,5) and (10,0) along the line. Staples are located on the vertical axis, whereas paper clips are located on the horizontal axis. Therefore, boxes of: A) staples cost twice as much as boxes of paper clips. B) paper clips cost twice as much as boxes of staples. C) staples cost $10. D) paper clips cost $5. E) staples cost the same as boxes of paper clips