I'm taking a test and have to guess the right answer to the question after the article. Article: As each semester begins, my colleague greets his students wearing a jacket and tie. "You make only one first impression," he says. So while the rest of the semester he teaches class in his usual, more casual clothes, the first week he presents a different image. His thought is that students will remember their first meet positively and more readily think highly of him as the semester goes on because that favorable first impression has an influence on them. The sequence that we meet matters in how we judge subsequent information. The big influence of first impressions is related to the halo effect, where the perception of positive qualities in one thing or part gives rise to the perception of similar qualities in related things or in the whole. Here is an example: You meet a friendly person at a party and later are asked to collect money for a worthy cause. You call that person because you think she will make a contribution. In reality, there is no connection between being pleasant and being generous. Yet the halo effect leads you to think that the two are related. The halo effect is powerful, but it is questionable whether it matters much in long-term relationships, such as that between teacher and student. While dressing up may make students think the teacher must know his subject matter because he creates a professional first impression, the effect wears thin if the person turns out to be a poor teacher after all. First impressions matter but they don't have the final word. Facts speak louder. If you had never seen or heard of Einstein, the first time you saw him your impression would most likely be negative. Now his face is connected with genius , not madness because he is the person who has come to define what genius is. The problem is that few of us are Einsteins and we often don't get the chance to change a negative first impression. Question: The author explains the halo effect mainly by _ . Options: A: following the order of importance B: making a comparison C: setting down general rules D: giving an example
D