Great explanation of (A) above!
In case any future students are struggling with this question, here's a full explanation.
The stimulus provides us this basic argument:
Corelink must be cheap enough to be within budget.
Why? Because it's cheaper than QI, which is in within budget.If you wanted to boil it down further, it could be: C is low enough, because C is lower than Q and Q is low enough.
Let's do a conclusion match sweep. We're looking for something with an entity passing muster:
(A) OK
(B) OK
(C) IFFY since it's illegal, but OK
(D) Eliminate - "just right"? What is this, Goldilocks?
(E) OK
Now let's do a premise match sweep. We're looking for something else to be "passable" -and the thing we're discussing in the conclusion to be more passable than that.
(A) OK
(B) OK
(C) Eliminate - "even if it turns out" is a mis-match
(E) OK
Now, let's look at the logic of (A), (B) and (E).
(A) and (B) are both about ability to do something, and this prevents the premise from truly supporting the conclusion, since ones ability to perform an action - be it jumping or running a marathon - probably depends on more than one factor. Just because someone is taller than someone who can jump X feet high, doesn't mean this taller person can. Same thing applies to marathon-running!
(E) is a match: one thing must pass because it is even lower than another thing that passes on that criteria. No cow jumping over the moon required.