The key to answering this question is to correctly understand the meaning of this sentence. This sentence tells us that often being with people with noble character is like bathing in a room full of fragrance when planting Lan Zhi. After a long time, I can't smell the fragrance, but it is already full of fragrance. Being with people with bad conduct is like going to a place selling abalone. After a long time, I can't smell it, but I am also integrated into the environment. In short, it is near Zhu Zhechi, and those who are near Mexico are black. Therefore, we should be careful to make friends; Therefore, option c meets the meaning of the question; B didn't grasp the principle of making friends; C is the expression of "buddy loyalty"; D does not conform to the principle of making friends; So choose a.