求助:xdf逻辑专册56题

Which of the following most logically completes the argument?

When people engage in activities that help others, their brain release endorphins, the brain's natural opiates, which induce in people a feeling of well-being. It has been suggested that regular release of endorphins increase people's longevity.

And a statistic on adults who regular engage in volunteer work helping others shows that they live longer, on average, than adults who do not volunteer. However, that statistic would be what we would expect even if volunteering does not boost longevity, because____.

A.  in the communities studied, women were much more likely to do regular volunteer work than men were, and women tend to live longer than men do.  

C.  the feeling of well-being induced by endorphins can, at least for a time, mask the symptoms of various conditions and diseases, provided the symptoms are mild.

答案是C,但我总觉得A更好.C感觉少了一个假设:判断longevity的标准是这个人看起来是否健康.

A没有关系，因为统计可以更具体到性别，这个不是合理的逻辑变量。并且，这个男人，女人与成年人之间是无关的。

C并没有说longevity的标准是健康。

这句话的意思是，统计仍然是我们所期望的，即使自愿不能使人长寿，它的生理特性能使人们更好的应对疾病和困境。

I do not know where you get the answer. A should be the answer. The answer should suggest a reason why the statistic keeps same even if the volunteering does not enhance longevity. A points out that the statistic comes out just because the subjects invetigated tend to live longer, not because they volunteer. So A should be the answer. C actually says nothing. So impossibly be the answer.

谢谢lawyer的指点!