The correct option is C. It shows a positive effect of the solution.
The topic of the presentation is the impact of excessive homework on highschool. The word "excessive" implies that the amount of homework given at highschool has a negative effect on students. The solution would be to have "less homework" and she finds out a positive effect of such a solution. If students are given less homework, they will have time to do other enriching activities and spend time bonding with their loved ones.
A metaphor means you say figure of speech, Like <span>the leaves danced in the trees delighted that spring had finally arrived.</span>
