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 factor, since in the United States 60% 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 this 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 ini 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.

OA is E
What's the logic here? Is "SV40 virus is a contributing factor" also not a conclusion that we need to weaken? Why is " Researchers hypothesize that this vaccine was ..." the only hypothesis ?

Thanks for your help.

This is a tricky one. Initially I thought the answer was C but on closer reading it's E

Here is my reasoning

Researcher's Hypothesis : vaccine was the source of this virus found in mesotheliomas


POE

A : Irrelevant. How does it matter if it's widely used
B : Irrelevant . Doesnt matter in the current process
C: Close call - keep it
D : Irrelevant. Small percentage of cases doesnt help to strengthen the hypothesis
E : Keep it

Between C and E

Mesothelioma - Primary cause Asbestos
Contributing Factor -SV40
60% of Tissue samples of meso* contain SV40
SV40 - Polio vaccines were contaminated with the virus

Ans C talk about traces of virus found in the vaccine. But doesnt talk about the traces of virus in cases of meso*
There is a scope shift

Ans E Strongly says that vaccine was not contaminated and that samples of meso* did not contain SV40
Which means the only source possible for a tissue affected by meso* to contain SV40 is from the vaccine


I think this is pretty tricky

wait, what? why would you have to weaken anything?
the problem asks you to strengthen the argument, not to weaken it.

you are correct in asserting that there are essentially 2 hypotheses in this passage. however, there are two extremely strong indications that you should only be considering the second one (the final sentence of the passage):
1: none of the answer choices strengthen the assertion that sv40 is a contributing factor.
2: the last sentence starts with 'researchers hypothesize'. since the question prompt refers to a 'hypothesis', you can be pretty sure this is the one.