The correct answer is D.
The teacher clearly dislikes his students; he describes their work as slovenly and says that he is sick and tired of dealing with them.
He explains that he will not take the last of his energy and waste it on them, since they are so indifferent. While he does not like them, he does not yet hate them. He says if he were to give them the last of his energy, however, he would end up hating them. For now, though, he just dislikes them and waits for the bell.
If you want something I suggest about manatees?
The answer would be A. The reason for this is it is the most likely answer. old people makes no sense. a retirement home has nothing to do with the question and work over the years does not correctly define legacy.