Why are some people willing to participate in social activities and make friends, but some people can't avoid it? Some researchers have proposed that compared with others, the CD38 gene has a higher expression level, and people with specific mutations in the CD157 gene sequence are more likely to socialize. So these two genes affect people's social ability. However, some opponents have suggested that human's social ability is determined by the oxytocin located in the long arm 1 region of human chromosome 4, which can be synthesized by the brain of both men and women. A hormone that has an important effect on a person's social ability. Which of the following, if true, would most weaken the opponent's point of view? ['C. D.38 and C. D.157 genes control oxytocin secretion.', "The secretion of oxytocin affects people's empathy, trust and generosity, etc.", 'Which of the two genes mentioned above has a greater impact on human social ability is still uncertain.', 'Whether gene expression can affect behavior depends to a large extent on the social environment in which people live.']