How does the approach for "Weaken the argument" questions differ from that for "Weaken the conclusion" questions? Is it necessary that for the former, we must only focus on the premise and choose an answer that won't really affect the conclusion but weakens the premise/argument?
Here is an example:
Advertisement: The world’s best coffee beans come from Colombia. The more Colombian beans in a blend of coffee, the better the blend, and no company purchases more Colombian beans than Kreemo Coffee. Inc. So it only stands to reason that if you buy a can of Kreemo’s coffee, you’re buying the best blended coffee available today.
The reasoning of the argument in the advertisement is flawed because it overlooks the possibility that
(A) the equipment used by Kreemo to blend and package its coffee is no different from that used by most other coffee producers
(B) not all of Kreemo’s competitors use Colombian coffee beans in the blends of coffee they sell
(C) Kreemo sells more coffee than does any other company
(D) Kreemo’s coffee is the most expensive blended coffee available today
(E) the best unblended coffee is better than the best blended coffee
The answer is C. I get it, because Kreemo claims that just because it purchases more beans, its coffee would contain more beans or whatever. But this does not necessarily weaken the conclusion. In fact, it might be selling more coffee because it might as well be the best available brand of coffee.