I am stillnot able to understand why Option C is wrong

The plan is to stop producing cotton, and start producing soybeans.
Therefore, anything that makes cotton less attractive will only strengthen the plan. This is what C does, by telling us the price for cotton hasn't gone up.
So C strengthens, not weakens, the plan.
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Another take on C - what C is trying to do is suggest that without a sharp increase in demand, then the conclusion that "cotton will increase their income significantly" is invalid. But note that there are two factors in classic pricing: supply and demand. And the first sentence of the stimulus shows us that supply is down *and* even more importantly that prices are way up ("dramatic increases in the price"). So we don't need a sharp increase in demand like C might make us think - we already know that the price is up. And note that the conclusion even says "at least in the next several years," suggesting that we don't need this shortened supply to last forever or demand to kick up sharply - the conclusion is limited to this time frame in which we know that the price is up.


Insect infestations in certain cotton-growing regions of the world have caused dramatic increases in the price of cotton on the world market. By contrast, the price of soybeans has long remained stable. Knowing that cotton plants mature quickly, many soybean growers in Ortovia plan to cease growing soybeans and begin raising cotton instead, thereby taking advantage of the high price of cotton to increase their income significantly, at least over the next several years.

(C) In the past several years, there has been no sharp increase in the demand for cotton and for goods made out of cotton.
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Let's stay focused on the conclusion we're given, then ask whether choice (E) weakens that specific conclusion.

We know that the plan is for soybean farmers to cease growing soybeans and begin raising cotton instead. This plan will "increase [the farmers'] income significantly" by taking advantage of the high price of cotton. The correct answer choice is the one that most seriously weakens the plan's chance of success.

Answer choice (E) states:

This tells us that soybean plants have never been attacked by the insects that infested the cotton plants. Therefore, it's unlikely that this insect infestation will affect soybean plants in the same way it has affected cotton plants.

So what? This information does not weaken the plan's chance of success, because it does not change the evidence that the farmers used to justify their plan in the first place (the dramatically high price of cotton and the stable price of soybeans). If anything, this choice reinforces why we expect the price of soybeans to remain stable.

As for your analysis: yes, you're sliding into "if/maybe" here. Let's clarify.

The passage states that the insect infestation occurred in "certain cotton-growing regions of the world." Answer choice (E) does not provide any evidence that Ortovia is in one of those regions. Also, the fact that soybean plants are not attacked by the same species that infested cotton plants does not provide any evidence that this species does live in Ortovia. Therefore, we cannot infer that the insects are present based on the information in the answer choice.

On the other hand, the information provided by answer choice (B) directly undermines the plan by providing a reason to doubt that the cotton infestation will continue -- consequently lowering expectations that the dramatic increases in the price of cotton will last. So (B) is a much better option than (E).

I hope that helps!
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The supply has decreased because the insect infestations have reduced the yields, yeah?

(B) Tests of a newly developed, inexpensive pesticide have shown it to be both environmentally safe and effective against the insects that have infested cotton crops.

Weaken's most seriously weakens the plan’s chances for success

IMO B
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P1: Cotton prices are up
P2: Soybean prices are stable
C1: Price of cotton will remain high over several years, so they will increase their income significantly by growing it

(A) The cost of raising soybeans has increased significantly over the past several years and is expected to continue to climb.
Opposite, actually strengthens somewhat.

(B) Tests of a newly developed, inexpensive pesticide have shown it to be both environmentally safe and effective against the insects that have infested cotton crops.
Gives an alternate reason why this plan wouldn't work. Presumably the pesticide will be used and production will return to normal levels, lowering the price.

(C) In the past several years, there has been no sharp increase in the demand for cotton and for goods made out of cotton.
Doesn't help weaken, if demand is equal to prior levels then there is still a gap in the supply needed to fill it.

(D) Few consumers would be willing to pay significantly higher prices for cotton goods than they are now paying.
Completely out of scope.

(E) The species of insect that has infested cotton plants has never been known to attack soybean plants.
Opposite, actually strengthens.

Plan: cease growing Soy, grow cotton to take advantage of high price of cotton to increase income significantly
p1: inset infestations caused dramatic increases in price of cotton on world market
p1:price soybeans remain stable

Weaken chance for success:
A - Incorrect - Increase in Soy doesn't weaken chance for success of Cotton
B - (potentially - could alleviate problem causing prices to be so high)
C - Incorrect- no sharp increase doesn't impact current high price of Cotton
D - Incorrect - they are currently paying 'high' prices, and the plan doesn't say anything about charging "higher" amounts
E - Incorrect - Doesn't impact the plan to grow cotton, it just solidifies the case that Soy is stable
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Yes, they also changed the question a bit and moved a sentence of the argument.

The question stem:

"Insect infestations in certain cotton-growing regions of the world have caused dramatic increases in the price of cotton on the world market. By contrast, the price of soybeans has long remained stable. Knowing that cotton plants mature quickly, many soybean growers in Ortovia plan to cease growing soybeans and begin raising cotton instead, thereby taking advantage of the high price of cotton to increase their income significantly, at least over the next several years.

Which of the following, if true, most seriously weakens the plan’s chances for success?"

has been replaced with

"Insect infestations in certain cotton-growing regions of the world have caused dramatic increases in the price of cotton on the world market. Knowing that cotton plants mature quickly, many soybean growers in Ortovia plan to cease growing soybeans, the price of which has long been stable, and to begin raising cotton instead, thereby taking advantage of the high price of cotton to increase their income significantly at least over the next several years.

Which of the following, if true, most calls into question the reasoning on which the plan is based?"

Conclusion: [many soybean growers in Ortovia plan to cease growing soybeans, the price of which has long been stable, and to begin raising cotton instead] taking advantage of the high price of cotton to increase their income
Prethink: what if everyone switching over crops deflates the price? The insect infestation presumably destroyed the cotton crops in certain regions, raising the prices because of a shortage (presumably). If everyone hops over and there’s a surplus, this could normalize the price.

A. The cost of raising soybeans has increased significantly over the past several years and is expected to continue to climb.
Out of scope/opposite – we don’t care about the cost of raising SOYBEANS. We want to focus on the cotton plants and how it could potentially be beneficial to growers. But if anything, this raising cost of soybeans would give more the reason for farmers to hop over to cotton, enabling farmers to take advantage of the high price of cotton.

B. Tests of a newly developed, inexpensive pesticide have shown it to be both environmentally safe and effective against the insects that have infected cotton crops.
Bingo. This would remove the piece that boosted up prices of the cotton, resulting in a normalized price.

C. In the past several years there has been no sharp increase in the demand for cotton and for goods made out of cotton.
Out of scope – This more targeted towards the past. The farmers’ intentions lie within the future. B is a stronger weakener.

D. Many consumers consider cotton cloth a necessity rather than a luxury and would be willing to pay significantly higher prices for cotton goods than they currently pay.
Opposite – this further substantiates and provides another reason for why the prices are going up. Would further support the farmers’ reasoning to jump ship.

E. The species of insect that has infested cotton plants has never been known to attack soybean plants
This keep everything neutral. Doesn’t affect the argument at all. If anything, this would help support because this would provide more clarity.

I guessed answer C and I haven't seen anyone argue my logic, so here it goes:

Currently, let's say that the supply of cotton is at 100 before the soybean farmers enter the cotton market. Let's also assume that the demand = 100, so there's a 1 to 1 relationship. If there has been no sharp increase in demand, then the supply will increase when the soybean farmers enter the market. Let's say this shifts the supply to = 200. What happens when there's any increase in supply while holding demand constant? The prices go down.

If the prices go down, then the income of the farmers will be reduced.

I realize that this answer requires too many assumptions / logical bounds, but just wanted to share my thoughts incase someone else had them .

Answer is B, btw .

Thanks BostonTC2018 for sharing your thoughts. But you missed some points of other side.

Currently, let's say that the supply of cotton is at 100 before the soybean farmers enter the cotton market. Let's also assume that the demand = 100, so there's a 1 to 1 relationship. If there has been no sharp increase in demand, then the supply will increase when the soybean farmers enter the market. Let's say this shifts the supply to = 200( not necessary, why?).


Because you missed KEY POINT: Insect infestations. It is because of Insect infestations, prices of cotton are high. Who knows after farmers produce supply, maybe 90% get infested? ( 90% would weaken the conclusion) but what if 1% get infested( then it strengthens) . In short, I have open end with this option.

Second Hint: What happens in history , how can you guarantee that same thing will happen in future. Example: Maybe in past several years, Insect infestations was not severe. But suddenly supply is reduced to minimal. All have open ends . So we cant weaken the conclusion.

In B , we have limited challenges. Now we have environmentally safe , inexpensive pesticide and effective against cotton.
What more else do you want?
Now you can not challenge B as much as you can challenge C.

Did you enjoy reading my analysis ?

I hope it helps:)

Let’s look at the premises and conclusion of the argument-


Insect infestations have caused dramatic increases in the price of cotton on the world market
the price of soybeans has long remained stable
cotton plants mature quickly

soybean growers’ plan (what we have to weaken)

to cease growing soybeans and begin raising cotton instead, thereby taking advantage of the high price of cotton to increase their income significantly, at least over the next several years.

The plan is to substitute soybean with cotton to take advantage of the high price of cotton and increase their income significantly.

(A) The cost of raising soybeans has increased significantly over the past several years and is expected to continue to climb.
This only provides all the more support to the soybean growers to cease growing soybeans and begin raising cotton instead. Eliminate.

(B) Tests of a newly developed, inexpensive pesticide have shown it to be both environmentally safe and effective against the insects that have infested cotton crops.

In that case, it will affect the dramatic increase in the price of cotton. If there’s no increase in the price of cotton, then the plan of soybean growers to cultivate cotton instead of soybeans will be in vain. This weakens the plan’s chances for success and is hence the correct answer.

(C) In the past several years, there has been no sharp increase in the demand for cotton and for goods made out of cotton.
The premise states that there has been a dramatic increase in the price of cotton. Option C does not impact the conclusion. Eliminate.

(D) Few consumers would be willing to pay significantly higher prices for cotton goods than they are now paying.
The conclusion is drawn on the basis of the current prices. Eliminate.

(E) The species of insect that has infested cotton plants has never been known to attack soybean plants.
Not relevant. The plan is to cease growing soybeans and grow cotton instead. Eliminate.

Vishnupriya
GMAT Verbal SME
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What you are saying makes sense, but think of this, referring to option E, what if the pests were ever present but did not attack the soyabean plants, so never realized, once the shift is made, they may well infest the cotton produced by these farmers?