CR

[Soumita]

It is difficult to find the precise cause of any disease resulting from B-vitamin deficiencies. For example, it is known that a deficiency in all the B-vitamins causes the disease beriberi and that beriberi is always accompanied by a deficiency of vitamin B1. However, in a recent study, human volunteers did not contract beriberi despite being fed a special diet that was deficient in B1.

Which of the following if true best explains the results above?

A) Some individuals whose diets lack vitamin B1 will contract beriberi if they consume a generally unhealthful diet.
B) A deficiency in vitamin B1 is not necessary to contract beriberi.
C)Beriberi can be cured by any variety of B-vitamin supplements.
D)Beriberi is caused by deficiencies in a combination of B-vitamins.
E)Deficiencies in the B-vitamins have widely varying effects on different individuals, so that specific diseases cannot be adequately identified.

I eliminate A as option A stated that some individuals whose diets lack vitamin B1 will contract beriberi if they consume a generally unhealthful diet. Lack of vitamin B1 in diet is itself unhealthful diet. So I eliminate A.

I chose E as option E stated that deficiencies in the B vitamin have widely varying effects on different individuals,so that specific diseases cannot be adequately identified. This statement explain the result. The test result was different as person volunteer has different effect when he was fed a diet lack in vitamin B1.

OA is D. Can anyone explain me why E is eliminated.Where I am wrong?

Pls help me !!

[Jim@StratusPrep]

You are trying to break down the link between a deficiency of B1 to Beriberi.

E does not directly break down this relationship. D does this by saying it is not a deficiency in B1, but rather a deficiency in many vitamins.

Jim

[ceilidh.erickson]

When you're looking to explain an outcome on a CR argument, you have to pick an answer choice that does 2 things: 1) keeps the original premises true, and 2) supports the outcome that was found.

In this case, the original premises are:
- deficiencies in all B vitamins cause beriberi
- beriberi is always accompanied by deficiency in B1

outcome:
- deficiency in only B1 did not lead to beriberi

So what information are we missing? We don't know whether there's some other B vitamin that is also always deficient in beriberi sufferers. In other words, we're told that lack of B1 is a necessary condition for beriberi, but we don't know that it's the only necessary condition.

The problem with answer choice E is that it seems to undermine the given premises. If B-vitamin deficiencies affected different people differently, it wouldn't necessarily be true that a lack of B1 is always associated with beriberi. But we're told that that's true! So E can't provide that explanation.

We need to know what else is always associated with beriberi, which D explains.

Hope this helps!