From 1900 until the 1930s, pellagra, a disease later discovered to res

From 1900 until the 1930s, pellagra, a disease later discovered to result from a deficiency of the vitamin niacin, was common among poor cotton farmers in the United States whose diet consisted mostly of corn, the least costly food they could buy. Corn does not contain niacin in usable form. Curiously, during the Depression of the early 1930s, when cotton's price collapsed and cotton farmers’ income declined, the incidence of pellagra among those farmers also declined.

Which of the following, if true, most helps to explain the decline in the incidence of pellagra?

(A) When growing a cash crop could not generate adequate income, poor farmers in the United States responded by planting their land with vegetables and fruits for their own consumption.
Correct...
Since the farmers changed their diet, the changes occured.

(B) People whose diets consist largely of corn often suffer from protein deficiency as well as niacin deficiency.
Out of scope

(C) Until the discovery of pellagra's link with niacin, it was widely believed that the disease was an infection that could be transmitted from person to person.
Again, not close by. Out of scope

(D) Effective treatment for pellagra became available once its link with niacin was established.
we are not talking of treatment but drop in cases

(E) In parts of Mexico, where people subsisted on corn but pellagra was uncommon, corn was typically processed with alkaline substances, which make the niacin in the corn absorbable.
we are not talking of Mexico. We cannot relate what happened there with USA

A
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Let's take a look at the passage to check the argument before we look at how (A) explains the decline in pellagra.

The passage tells us:

1) Pellagra results from a niacin deficiency
2) Cotton farmers commonly had pellagra from 1900 until the 1930s
3) These farmers' diets commonly consisted mostly of corn -- the only crop they could afford
4) Corn does not contain niacin in a form the body can use
5) In the 1930s depression, the cotton price collapsed and farmers' income declined

This question asks us to find the answer choice that best explains why incidences of pellagra also declined in the 1930s, in the midst of the depression.

(A) tells us:

We were told in the passage that the cotton price collapsed in the 1930s. From this, we can infer that at least some farmers were not able to generate an adequate income from their cotton farms. (A) tells us that these farmers would respond by "planting their land with vegetables and fruits for their own consumption."

It is the addition of a greater amount of vegetables and fruits in the farmers' diets that could explain the decline in the incidence of pellagra. The implication is that the vegetables and fruit contain the extra niacin the farmers' bodies needed to prevent them from developing pellagra.

While there isn't an EXPLICIT link between the farmers eating a greater amount of vegetables and fruit and the lower incidence of pellagra, this is ok. The question asks us to find the answer choice that most helps explain the decline in the incidence of Pellagra. Since the implied link between fruit and vegetable consumption in (A) does more to explain the decline in pellagra than any other answer choice, it is the answer to this question.

I hope that helps!
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Question Type: Explain/Paradox

Argument: Corn is cheap and doesn't contain niacin. Farmers --> poor --> consume corn --> suffer from vit. deficiency i.e. Pellegra.
Farmers income decreased further. However, Pellegra incidence also reduced.

(A) When growing a cash crop could not generate adequate income, poor farmers in the United States responded by planting their land with vegetables and fruits for their own consumption. - Correct. The diet of poor farmers was diversified and hence essential vitamins were consumed, thereby resulting in fewer incidences of Pellegra

(B) People whose diets consist largely of corn often suffer from protein deficiency as well as niacin deficiency. - Irrelevant.

(C) Until the discovery of pellagra's link with niacin, it was widely believed that the disease was an infection that could be transmitted from person to person. - Again irrelevant.

(D) Effective treatment for pellagra became available once its link with niacin was established. - Out of focus. We are worried about the incidence of Pellegra and not about its treatment.

(E) In parts of Mexico, where people subsisted on corn but pellagra was uncommon, corn was typically processed with alkaline substances, which make the niacin in the corn absorbable. - Incorrect for 2 reasons. 1: Talks about Mexico. 2: Talks about the area where Pellegra is uncommon.

Answer: A

I didn't choose A because I think the new diversified diet doesn't necessarily contain vitamin niacin. The choice doesn't at all address this explicitly, so more vitamin niacin (leading to lower incidence of pellagra) derived from consuming veg and fruits is not an obvious inference from choice A.

Hi Sagar

You are correct that we cannot say for sure that consumption of these fruits and vegetables would have filled the niacin vitamin deficiency in the farmers.

However, our task on the GMAT is to select the best possible option among those provided. Even this question asks us to select that option which most helps to explain the decline in pellagra infection.

Assessing the stimulus, we are looking for that answer option which provides an alternative way for the niacin deficiency to be overcome. Option (A) is the only answer option which provides such an alternative and hence it has to be the correct answer.

Remember - we have to work with the options given and choose the best among those always rather than get stuck on the possibility of a utopian option.

Hope this clarifies.
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The answer is A.

We can find this answer using the

Precise

strategy, since the question gives us enough information to figure out what we are looking for.
We are told that cotton farmers consumed corn, which doesn't have enough Niacin, and thus suffered from pellagra. However, when they had less money, they stuffed suffering. What could explain this? Well, it follows from less pellagra that they consumed less corn (since this is what caused it), and the change in income could explain this. So, the farmers probably consumed less corn, and consumed something cheaper with more Niacin. This is exactly what (A) tells us: When growing a cash crop could not generate adequate income, poor farmers in the United States responded by planting their land with vegetables and fruits for their own consumption.

Dear experts,

Though the correct answer is A), I am still unable to link how growing vegetables and fruits for own consumption has anything to do with decrease in the cases of Pellegra.

Kindly help!

Thanks

A should be the correct answer.

E is incorrect though tempting as it talks about mexico and it is not giving any proper reason why the number of people suffering from pellagra declined while farmers' income dwindled and cotton price declined.

With (A), as it talks about consumption of other food items during the Depression.
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What is the paradox here. ? farmers usually eat corn. and corn does not consist niacin. however when production of cotton decreased, so does the incidence.evidently it has something to do with cotton and nothing to do with corn. Option A is on same lines and must be the answer.

Which of the following, if true, most helps to explain the decline in the incidence of pellagra?

(A) When growing a cash crop could not generate adequate income, poor farmers in the United States responded by planting their land with vegetables and fruits for their own consumption.

Imo A

A is our answer as when the cotton prices collapsed then the farmers had no choice other than to plant other crops such as vegetables, leading to decrease in cases of pellagra.

B Irrelevant as we not concerned protein deficiency.

C Again it is irrelevant

D Well this choice is tempting but we are not concerned with the treatment of the pellagra. This may be true but we do not know whether the treatment became available in 1930 or later .

E Irrelevant

Yes! For the same reason, I did not choose Choice A, though seemed convincing at first. Can someone please explain?

BhaveshGMAT the reason behind A is selected is because its a better choice among rest.
Let's decode options one by one.

(B) People whose diets consist largely of corn often suffer from protein deficiency as well as niacin deficiency. (We can't infer that the corn consumption leads to any protein deficiency because passage don't mention such even a single time. Even if the corn consumption Leads to protein deficiency in reality, we can't conclude in passage, because it never mention so) (Incorrect)

(C) Until the discovery of pellagra's link with niacin, it was widely believed that the disease was an infection that could be transmitted from person to person. (The farmers/researchers wouldn't have known that pellagra is caused due to Vitamin niacin deficiency, if it hadn't been discovered by then. The passage states in the initial lines itself that the pellagra is caused due to niacin deficiency, hence the paradox here is wrong) (Incorrect)

(D) Effective treatment for pellagra became available once its link with niacin was established.(The farmers couldn't even afford niacin efficient food supplies how can they afford its medicine? It can't be the cause of decreased level of deficiency) (Incorrect)

(E) In parts of Mexico, where people subsisted on corn but pellagra was uncommon, corn was typically processed with alkaline substances, which make the niacin in the corn absorbable. (Even though this seems best, the sole reason we can't take this is because it mentions Mexico in its reference, we can't say the same situation is generalized everywhere else) (Incorrect)

Now, Since None of the options Above is good enough we are left with option A only.

(A) When growing a cash crop could not generate adequate income, poor farmers in the United States responded by planting their land with vegetables and fruits for their own consumption.(even though its stating an hypothetical situation but what if the farmers did grew vegetables and fruits back then which improved their pellagra situation? The deficiency level would had decreased then.)

This statement might or might not be the perfect answer, but is surely the only half valid point among rest.

Posted from my mobile device
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Hi Sagar

The passage states the following about Pellagra:

i) ...pellagra, a disease later discovered to result from a deficiency of the vitamin niacin
ii) cotton farmers in the United States...diet consisted mostly of corn
iii) Corn does not contain niacin in usable form

After the Great Depression, as per option (A), "...poor farmers in the United States...planting their land with vegetables and fruits for their own consumption". Fruits and vegetables are an excellent source of vitamins. Therefore, presumably, consumption of these fruits and vegetables filled the niacin deficiency that these farmers earlier had due to consumption of primarily corn, leading to a lower incidence of pellagra.

Hope this helps.
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I agree to your point that consumption of fruits and vegetables presumably could fill the vitamin deficiency. But how can we say for sure that the fruits and vegetables helped fill in the vitamin niacin deficiency

Posted from my mobile device

I think it is pretty straightforward, the rationale being there has to be something in the diet which helped famers keeping the disease at bay

(A) When growing a cash crop could not generate adequate income, poor farmers in the United States responded by planting their land with vegetables and fruits for their own consumption: Bingo, this matches our requirement

(B) People whose diets consist largely of corn often suffer from protein deficiency as well as niacin deficiency: where does protein came from??

(C) Until the discovery of pellagra's link with niacin, it was widely believed that the disease was an infection that could be transmitted from person to person: doesn't help with the resolution of the paradox

(D) Effective treatment for pellagra became available once its link with niacin was established: it does not matter

(E) In parts of Mexico, where people subsisted on corn but pellagra was uncommon, corn was typically processed with alkaline substances, which make the niacin in the corn absorbable: So what??

Thank you #GMATNinja! I was adamant, questioning 'How can we imply the relationship between the two?'. The fact that the question asks us to find an answer that 'most helps' explain the cause, it now makes sense why we would go with answer choice (A).

This is actually an excellent question, not sure why its marked just 15% . Here's my detailed explanation.

(A) When growing a cash crop could not generate adequate income, poor farmers in the United States responded by planting their land with vegetables and fruits for their own consumption.
At first, this may look out of scope considering a change in diet from corn to fruits and vegetables can mean - Same Niacin deficiency, decreased deficiency & increased deficiency. Afterall, no-one knows whether fruits & vegetables give help in absorbtion of niacin. However, it does make us believe to some extent that a change might have occured. Lets keep this.

(B) People whose diets consist largely of corn often suffer from protein deficiency as well as niacin deficiency.
We don't really care about a protein deficiency along with niacin deficiency. We just need to find out a possible reasoning for the decreased incidence of pellagra among the United states farmers after 1930 OR if simply put, a reason for how the niacin absorbtion may have increased. Eliminate

(C) Until the discovery of pellagra's link with niacin, it was widely believed that the disease was an infection that could be transmitted from person to person.
Even if it was believed to have transmitted, does that help us give a possible reasoning for the decreased incidence of pellagra among the United states farmers? Eliminate

(D) Effective treatment for pellagra became available once its link with niacin was established.
The question stem very clearly mentions about "the incidence of pellagra among those farmers also declined" . Even if an effective treatment was available, does it give us a reason for decreased incidence or occurence of the disease? The disease could've easily been equally or more frequent, what changes because of this option is probably the recovery rate. Eliminate

(E) In parts of Mexico, where people subsisted on corn but pellagra was uncommon, corn was typically processed with alkaline substances, which make the niacin in the corn absorbable.
Mexico? Where did Mexico come from? The argument clearly talks about only US farmers, and for our answer choice, we should stick with only those specific kind of farmers. Eliminate