Critical Reasoning

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.

bryan88 wrote: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.

My explanation is:

Argument says that beriberi is always accompanied by a deficiency of a vitamin B1. But in this case when a special diet that was deficient in B1 did not cause beriberi.. So there is some other cause...but this cause should not negate the premise that vitamin B1 deficiency causes beriberi.

A: this doesn't explain why the volunteers got beriberi.. that too it states the same thing what is already stated in the argument... ELIMINATE
B: This is attacking the premise "beriberi is always accompanied by a deficiency of vitamin B1" so ELIMINATE..
C: Curing is not what is discussed or necessary here... so ELIMINATE...
D: This could be a valid answer... its the combination of B - vitamins which has caused the beriberi...
E: more generalized statement not explaining about the situation....ELIMINATE
My Answer is D...

Is this correct???... If anyone has some improved way to deal with this problem please explain... Thanks...
Hope the answer is D... Please do mention the Answer thanks....

Goal: Explain why volunteers did not contract Beriberi.

Both B and D seems correct.

B) A deficiency in vitamin B1 is not necessary to contract beriberi.
=> This explains why volunteers did not contract beriberi.

D)Beriberi is caused by deficiencies in a combination of B-vitamins.
=> Volunteers were deficient of only in vitamin B1 and not of other B vitamins, so volunteers did not contract Beriberi. This explains why volunteers did not contract beriberi.

Can some expert please advice how to select between B and D?

"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."

From the bold face part in the argument we can form the logic statement:

beriberi--> B1 deficiency
so B1 deficiency may or may not --> beriberi

i.e. A deficiency in vitamin B1 is not necessary to contract beriberi--> Option B

actually what option B does here is that it simply states the above logic and does nothing to add on to something we may need to answer the required question.

Whereas option D does provides us with a solid information to explain the study results.

Hence D is the correct one.

-->
B) A deficiency in vitamin B1 is not necessary to contract beriberi.

D)Beriberi is caused by deficiencies in a combination of B-vitamins.

hope this helps..!!!