[求助]大全-6-17

A researcher discovered that people who have low levels of immune-system activity tend to score much lower on tests of mental health than do people with normal or high immune-system activity. The researcher concluded from this experiment that the immune system protects against mental illness as well as against physical disease.

17.   The researcher’s conclusion would be most seriously weakened if it were true that

(A) there was a one-year delay between the completion of a pilot study for the experiment and the initiation of the experiment itself

(B) people’s levels of immune-system activity are not affected by their use of medications

(C) a few people with high immune-system activity had scores on the test of mental health that were similar to the scores of people who had normal immune-system activity

(D) people who have low immune-system activity tend to contract more viral infections than do people with normal or high immune-system activity

(E) high levels of stress first cause mental illness and then cause decreased immune-system activity in normal individuals

答案E，不明白？

我想请教一下:C选项为什么错?

这没有说是B-A吧？

只是说精神疾病和免疫系统都是由于压力高而引起的啊？？

求助

(E) high levels of stress first cause mental illness and then cause decreased immune-system activity in normal individuals

说明high level of stree先破坏mental illness再影响immune-system,immune-system根本就没机会保护mental illness，自然削弱了结论： that the immune system protects against mental illness as well as against physical disease.