A teacher can't decide whether to use a point or percentage-based grading system. She knows that both have both advantages and disadvantages. Of the following, which is the most important disadvantage of a points-based grading system? Question content area bottom Part 1 A. It is harder for students and parents to understand. B. A percentage system requires more teacher time and effort. C. A percentage system emphasizes competition. D. A percentage system can't be done on a computer