这是个老题了，看了N久的讨论，也没太明白最终是E还是C，还请各位梦友，各位牛
牛们再次能确认一下。除了希望考试别碰到这样的题，难道不能弄个水落石出吗？争
论焦点主要在C 和E上。
简述一下前人的理论依据：C是有因有果的加强，E是无因无果的加强。
谢谢了。不懂的日子真郁闷！
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?
A. SV40 is widely used as a research tool in cancer laboratories.
B. Changes in the technique of manufacturing the vaccine now prevent
contamination with SV40.
C. Recently discovered samples of the vaccine dating from 1960 still show
traces of the virus.
D. In a small percentage of cases of mesothelioma, there is no history of
exposure to asbestos.
E. In Finland, where the polio vaccine was never contaminated, samples
from mesotheliomas do not contain SV40 | 
