If it is difficult to determine which foods cause migraines, then some foods that cause allergic reactions might not have been demonstrated to do so. Hence, if choice A is true, eliminating foods that have been demonstrated to cause migraines might not eliminate migraines, even if food allergies are the only cause of migraines. Choice A is the best answer.

Neither the fact that some food allergies do not result in migraines (choice B), nor the fact that few allergies result in symptoms more severe than migraines (choice E), explains why restricting one’s diet does not stop migraines. Choice C suggests that migraine sufferers do not naturally avoid the foods at issue. Choice D reiterates the information that eliminating certain foods does not usually solve the problem.
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Although migraine headaches are believed to be caused by food allergies, putting patients on diets that eliminate those foods to which the patients have been demonstrated to have allergic migraine reactions frequently does not stop headaches. Obviously, some other cause of migraine headaches besides food allergies must exist.

Which of the following, if true, would most weaken the conclusion above?

A.Many common foods elicit an allergic response only after several days, making it very difficult to observe links between specific foods patients eat and headaches they develop.

B.Food allergies affect many people who never develop the symptom of migraine headaches

C.Many patients report that the foods that cause them migraine headaches are among the foods that they most enjoy eating.

D.Very few patients have allergic migraine reactions as children and then live migraine-free adult lives once they have eliminated from their diets foods to which they have been demonstrated to be allergic.

E.Very rarely do food allergies cause patients to suffer a symptom more severe than that of migraine headaches.

Can anyone explain me why 'C' is incorrect? I do find the same topic that had been discussed few years back, but couldn't explore why 'C' is incorrect as the contest was b/w A and D. I got to know why A is correct, but couldn't get the reasoning for why we should make it C as wrong.

Only (A) weakens the conclusion.It could be that people can easily overlook the actual culprit foods that cause the migraine headache

If it is difficult to determine which foods cause migraines, then some foods that cause allergic reactions might not have been demonstrated to do so. Hence, if choice A is true, eliminating foods that have been demonstrated to cause migraines might not eliminate migraines, even if food allergies are the only cause of migraines. Choice A is the best answer.
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.It could be that people can easily overlook the actual culprit foods that cause the migraine headache . Hence A

now, I understand that studying the wrong options means studying how the pattern can be right + the common trap in gmat.

The key issue is most of the wrong options are stupid and have little values -> only the right answer is what test takers must learn.
Nevertheless, wrong options in one question can be the right answer in another question, or the wrong options contain a common trap.

Anyway, A is a very common and important pattern in gmat.

Greetings TarunTilokani,

I am no expert, but here are my 2 cents.

You have correctly identified the map to the correct answer, so I'll directly expand on how option (A) weakens the argument.

Although the author agrees that migraine headaches are caused by food allergies,

"putting patients on diets that eliminate those foods to which the patients have been demonstrated to have allergic migraine reactions frequently does not stop headaches".

The evidence above made him conclude that there must be some other reason.

As you've correctly figured out what our goal is-


So, lets attack on the reasoning presented.

(A) Many common foods elicit an allergic response only after several days, making it very difficult to observe links between specific foods patients eat and headaches they develop.

Option A correctly points out a flaw i.e. the food you believe you are allergic to might not be the reason for your headache, and you are unable to correctly figure out the food (root cause) that you are allergic to.

Why so? because any allergic would take several days to show an allergic response and thus it becomes a tedious task to figure out the food you are allergic to.

In a way what we have said is - YES! the reason for your headache is FOOD, just that you are unable to figure out which one.



Please let me know if you have any questions, would be happy to expand.

The argument is that some other cause of migraines besides food allergies must exist.
This is supported by the fact that a recent test was conducted on those who suffer from migraine headaches in which sufferers were put on diets that eliminated suspected foods believed to have caused said migraines.

We are asked to weaken the argument.
A is correct because if it is true that many common allergic responses to food occur only after several days, then this casts significant doubt over the conclusion drawn from the experiment conducted. The argument does not say anywhere that the researchers controlled for this factor in some way, so if they did not control for it then it would likely lead the researchers to draw an erroneous conclusion.
B is incorrect - we are only concerned with those who develop migraines from food allergies
C is incorrect although it does try to lure people. C is incorrect because the fact that the patients enjoy eating foods that cause them headaches does not negate the fact that when such foods are taken out of the patients' diet it would cease to cause migraines.
D is completely irrelevant - who cares if people who experience migraines are the same ones who don't live migraine-free. That doesn't affect the deduction made from the experiment.
E is incorrect because it doesn't matter whether other symptoms are solicited. We only care about migraine symptoms.
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