Nutritionist: Multivitamins are potent storehouses of antioxidants, s

One of the most often traps used in GMAT is “sampling” technique. (exactly what you see in statistic of Quant)

The form is:
Characteristics of the sample/sub-set is CORRECT
Conclusion: Characteristics for whole set/population is CORRECT too.

Assumption: the nature of characteristics of the sample and that of the whole set should be similar. If they are different, you can’t generalize the conclusion from information of the sample.

ANALYZE THE STIMULUS:

Fact: Multivitamins are potent storehouses of antioxidants (antioxidants of multivitamin – sample)
Fact: Studies that follow subjects over the course of many years—those who take multivitamins every day have a decreased longevity.
Conclusion: Clearly, if people want to live longer they should avoid antioxidants. (the whole population)

Which of the following is an assumption the argument relies on?

ANALYZE EACH ANSWER:

a) The use of antioxidants does not vary across different age groups.
Wrong. Out of scope. Nothing about “age groups”.

b) The less often one takes multivitamins, the more one’s longevity increases.
Wrong. Extreme assumption. Taking more often multivitamin decreases longevity, it does not mean taking less often multivitamins increase longevity. It may keep the longevity the SAME.

c) The antioxidants found in vitamins do not differ from antioxidants found in other sources, such as food.
Correct. C means we can generalize a conclusion from information of the sample, because the nature of information of the sample and that of the whole set is similar.

d) Antioxidants can confer health benefits that do not relate to longevity.
Wrong. Out of scope. Nothing about other benefits.

e) Antioxidants destroy free radicals, which are toxic to the body.
Wrong. Reverse answer. E may support the idea that taking more often multivitamin is good, not bad.

Hope it helps.