I'll address the popular options B, D, and E.
Option B: If most consumers already find you the cheapest, we understand that most consumers would purchase your tickets without the discount. So, this discount will reduce your price of ticket without increasing the number of tickets sold (because people buy your tickets in any case since you are the cheapest)
Option D: It says that people looking for cheap fares usually book their flights through independent websites rather than airline websites. But isn't that the problem Oriole was trying to solve its discount? Yes. It wanted to offer discounts so that people do not purchase tickets through independent website and rather come directly to its website. Actually, this option seems to suggest a rationale for offering the discount. Thus, this option supports the argument.
Let's look at the
opposite of option D - people looking for cheap fares usually book their flights through airline websites rather than through independent websites.
In this case, offering a discount doesn't make a lot of sense since people, in any case, are booking through the airline's website. Thus, the opposite of option D weakens the argument.
(We need not have done the exercise of looking at the opposite of option D. I did that just to be clear about the impact of D. If any option is a strengthener, its negation will be a weakener.)
Option E: It's quite difficult to comprehend. Even I had to spend extra time just to comprehend it. However, once I understood the option, it was not difficult to reject this option.
Oriole Airlines fares are generally not more than $20 less expensive than the least expensive fares from rival airlines for similar flights.
I
first tried to understand the following version of the option:
Oriole Airlines fares
are generally $20 less expensive than the least expensive fares from rival airlines for similar flights.
This statement means that fares of OA = least expensive fare from other airlines - $20
So, the statement means that the fares of OA are cheaper than the cheapest fares of other airlines by $20.
Having understood this statement, I take a jab at the original statement:
Oriole Airlines fares are generally not more than $20 less expensive than the least expensive fares from rival airlines for similar flights.
Now, I can understand this statement. So, $20 is the cap. OA fares are not cheaper by "more than $20" than the cheapest fares of other airlines.
Thus, the price advantage in favor of OA airlines is not more than $20.Now, having understood this statement, we can evaluate its impact on the argument.
Since it is a negative statement, I ask myself, "What if the price advantage in favor of OA airlines were more than $20?"
That would mean OA tickets are the cheapest by more than $20. This would weaken the argument, just as option B did.
Thus, the opposite of this option weakens the argument. Thus, option E is NOT a weakener.