答案是C，但我不知道E为什么不正确，因为E很象是ETS喜欢的取非样子。大家帮忙看看吧，谢谢了。
GWD-10-Q9:
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? | 
