14. The error was it was written that you would subtract the pages read by pages in the article which is incorrect. You would subtract pages total (5) by pages read (p). So it is 5-p.
The first definition is not as broad as it should be, therefore, while an angle does meet that criteria, it's not a general definition, hence, it is incorrect. The second one is incorrect as well because a parabola has a vertex, and it is certainly not an angle. This definition is not specific enough, so it will be eliminated. The last one is again, too specific. The third one is the best answer because it is broad enough while still being specific.