单选题 Studies have shown that people who rarely take antibiotics, which are antibacterial drugs, have stronger immune systems than do people who take antibiotics frequently. Yet there is no evidence that taking antibiotics weakens the immune system.
Which of the following, if true, best reconciles the apparent discrepancy in the information above?

A、 People who have strong immune systems seldom get the kinds of infections for which people normally take antibiotics
B、 People who have strong immune systems are seldom aware that their immune systems are unusually strong
C、 People who have weak immune systems have great difficulty recovering from bacterial infections if they do not take antibiotics
D、 Some people take antibiotics even though the antibiotics cause a variety of side effects
E、 Some people take antibiotics frequently because their doctors prescribe antibiotics for viral infections as well as for bacterial infections

【正确答案】 A

【答案解析】[解析] 本题的分歧之处在于没有证据表明吃抗生素会降低人体免疫功能，然而不吃抗生素的人的免疫系统比吃抗生素的人的免疫系统的功能更强。要解决这个分歧，就要找一个选项要么能说明抗生素确实能降低人体的免疫力，要么能说明不吃抗生素的人的免疫系统的功能较强是由他因所致。(A)选项指出免疫力强的人很少感染上人们通常用抗生素治疗的疾病，因而免疫力强的人，不吃抗生素；而免疫力差的人，感染上了疾病，就需要吃抗生素，所以(A)解释了本题段落中的分歧，为正确答案。