Although exposure to asbestos is the primary cause of mesothelioma, a slow-developing cancer, researchers believe that infection by the SV40 virus is a contributing cause, since in the United States 60 percent of tissue samples from mesotheliomas, but none from healthy tissue, contain SV40. SV40 is a monkey virus; however, in 1960 some polio vaccine was contaminated with the virus. Researchers hypothesize that this vaccine was the source of the virus found in mesotheliomas decades later.
Which of the following, if true, most strongly supports the researchers' hypothesis?
(A) SV40 is widely used as a research tool in cancer laboratories.
无关
(B) Changes in the technique of manufacturing the vaccine now prevent contamination with SV40.
now的事跟以前也无关
(C) Recently discovered samples of the vaccine dating from 1960 still show traces of the virus.
这句好像削弱。不知道我理解的对不对。
(D) In a small percentage of cases of mesothelioma, there is no history of exposure to asbestos.
无关
(E) In Finland, where the polio vaccine was never contaminated, samples from mesotheliomas do not contain SV40.其实这个选项也是部分支持，因为设定了范围在 Finland 但是相比之下，这个是最好的了。
E为正确答案， 请大家帮忙分析一下思路！
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