it appears that you may be misunderstanding the task at hand. this is a problem about strengthening/weakening arguments, not a problem about "assumptions".
in strengthening/weakening problems, you are given choices essentially out of nowhere, and asked to take them as true
for the purpose of evaluating their impact on the argument. this task is substantively different from dealing with assumptions, which are statements that must
be true for the argument to work.
yqren2002 wrote:Does the argument say which *type* of new stores will open in those locations??
this is one thing that makes me think you are misunderstanding the task itself.
you are correct that the original argument says nothing about which type of stores have been opening.
this is precisely why the correct answer choice is useful
-- because it provides information to fill in that particular gap.
I don't see any reason to make further assumption that only *discount* stores will open there.
"assumptions" are irrelevant here. if the answer choice actually says
that discount stores have been opening, then, ipso facto, we know that discount stores have been opening.
However, I do admit B is better than other options. Reasoning: old non-discounted stores could not compete with Colson so they were closed-->replaced with discounted stores-->current discounted stores will not be able to compete with Spendless so they will be closed-->therefore, if they are replaced with discounted stores again, new stores will fail similarlyã€‚
this is the exact reasoning required to solve the problem. so, at this point, i think it's pretty much certain that the problem is your misunderstanding the task itself on a fundamental level.
see the points above -- if you can "re-wire" your mind to think of this genre of problems in the right way, your reasoning here indicates that you should be quite good at them.
Although it's not supposed to get perfect answer for every question, this correct answer seems kind of far-fetched. I respect GMAT OG, OA and it's explanations. But again, I don't think this question is precisely designed :)
it's quite well-designed, and not at all "far-fetched". in fact, you just explained exactly how it works, and there is nothing implausible or improbable in your explanation.