Although exposure to asbestos is the primary cause for mesothelioma, a slow-developing cancer, researchers believe that infection by the SV40 virus is a contributing case, since in the US 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 toll 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

How did you eliminate C? And why is E the answer?

Other posts on MGMAT forum and this forum say that C states something we already know. I disagree.
the reasoning is:
Yes, we know vaccine was contaminated. But whether it could have an effect 40-50 years down the line is not known. So, knowing that those vaccine still have traces of SV40 gives a subtle new information that the virus can actually survive 40-50 years. So, it strengthens the hypotheses.

vaccine was contaminated with virus SV40 in 1960 ---> (Virus is still present in those vaccine samples of 1960 i.e. virus can survive 40-50 years) ---> vaccine is the source of virus found in cancer tissue.

To make things clear I tried to form an analogy:

David answers a question today. 50 years ago, David read a book that had the answer. The quiz master hypothesizes that reading that book helped David answer the question today.

Now, if we have to strengthen this hypothesis and 2 options are:

1. In a recent interview David mentioned that he remembers what he had read in that book.
2. Tom who never read the book, could not answer the question.

which one of the option would one choose?

Analogy:
David - Polio vaccine of US
Tom - Polio vaccine of Finland
Reading the book - contamination by virus
answering the question in quiz - virus in mesotheliomas
mentioned that he remembers - still show traces
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"Choose to chance the rapids and dance the tides"

thanks for reading the long post and replying back promptly and objectively.

And yes, you got it right. I am passionate about the answer option but only to the extent of it's logical worth.

Even I threw out C traversing from top to bottom. But on reaching E all options were eliminated So went back to find something.

E looked far fetched b'cos it says effect is absent and cause is absent too. Couldn't quite grasp, how absence of cause and effect, strengthen that cause-effect relationship.

But you are right, E is the best of all choices available. It does increase the chances that vaccine might be the source of virus.

kudos +1
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"Choose to chance the rapids and dance the tides"

Phew... After a big dilema between E and C went with C.

But E wins. Though not convinced much, but will take the causal effect relationship route.

Researchers hypothesize that vaccine -> virus in tissue.

Option E eliminates the possibility of the event happening even when the cause doesn't occur. (Power score route )
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D- Day December 30 2011. Hoping for the happiest new year celebrations !

Aiming for 700+

Kudo me if the post is worth it

First let us understand what the argument is about. All that is hypothesized is THE SOURCE OF virus; the argument does NOT INTEND to verify if the virus IS ALSO causing the cancer: it is just taken for granted (i.e., the virus can also contribute) and we can safely ignore it for the discussion.

Now, we need to prove that there is a possibility that the virus could have been due to contaminated vaccine.

We have 3 sets of people:

--> In US, two sets of people: ill people with contaminated vaccine + a virus and healthy people with clean vaccine + NO VIRUS.
--> In Finland, one set of people: ill people with clean vaccine + NO VIRUS.

from those 2 premises, we can conclude that the virus is due to contaminated vaccine and this is exactly what researchers hypothesized in the last sentence.

Note: there could be some other reason for the virus presence, but in the given context we can not eliminate the possibility of contaminated vaccine.

A very good question. Got confused for a some time.

If this helped you, consider KUDOS
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-Aravind Chembeti

THank you all for the explanation. they all helped me alot in this question.

What do you think the level of this question is?

Any more explanations why C is incorrect?
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