For this question I picked A:
From reading this passage, I immediately picked out the conclusion to be [highlight]"Thus, the price of cotton clothing will inevitably fall."[/highlight] If you are having trouble finding the conclusion, look for the conclusion marker "thus" and it should be easy from there.
The question stem then tells you that you are looking for an answer choice that weakens the argument.
The next step I took was to prephrase because this could potentially direct me to the correct answer and prephrasing forces me to think harder about what I just read.
So how did I prephrase this question? If you look back at the passage, you are essentially given a direct relationship between the price of raw cotton and the price of cotton clothing. This relationship makes sense if you
ASSUME that the processing/manufacturing from raw material to finished product has not changed in cost. Therefore, my first prephrase was: [highlight]An increase in manufacturing/processing costs.[/highlight] This would definitely weaken the argument because an increase in manufacturing costs would decrease the retailer's profit margins and may force the retailer's to leave their prices constant.
What is another possible prephrase? Well, it is possible that the retailer's themselves may have higher operating costs (ie. rent, electricity etc.) which would again squeeze the profit margins of the retailers. [highlight]Therefore, my second prephrase was: Increased operating costs of the retailers.[/highlight]
Now we can analyze each and every answer choice:
A. This answer choice matches one of my prephrases (My prephrase looks suspiciously similar to the answer choice, but I'm honestly telling you that I did not look at the answer choices until after my prephrasing. This should tell you the importance of doing this.) This is a definite contender and after looking at the other choices, I have determined that this is the correct answer.
B. The relationship in the passage is between price of raw cotton and the price of cotton clothing - the relationship between the price of raw wool and the price of raw cotton is irrelevant.
C. This answer choice is incorrect because it states that the operating costs have remained
CONSTANT. If this answer choice had said that the operating costs have increased, then this answer choice would definitely weaken the argument, but as it stands, this answer choice actually strengthens. The reason it strengthens is because it eliminates one of the reasons that could explain the error in the initial relationship.
D. This answer would be correct in a must be true question - it just summarizes what is already stated in the passage. Therefore, if anything, this answer choice strengthens.
E. The cost of harvesting should already be included in the wholesale price of raw cotton, therefore, this answer choice is irrelevant.