An eyeglass manufacturer tried to boost sales for the summer quarter by offering its distributors a special discount if their orders for that quarter exceeded those for last year's summer quarter by at least 20 percent. Many distributors qualified for this discount. Even with much merchandise discounted, sales increased enough to produce a healthy gain in net profits. The manufacturer plans to repeat this success by offering the same sort of discount for the fall quarter.
Which of the following, if true, most clearly points to a
flaw in the manufacturer's plan to repeat the successful performance of the summer quarter?
FLAW Questions : Key Point -Suppose X will lead to Y.
To point a flaw, you need to prove - X may / will not lead to Y. Now, with respect to this question,Offering discounts for summer quarters leads to increased sales thus increase in net profits.
Our task in hand for this question -- Offering discounts for fall quarter may / will not lead to increased sales thus increase in net profits. Now, look at the options keeping this approach in mind.
(A) In general, a distributor's orders for the summer quarter are no higher than those for the spring quarter.This option says - No. of distributor's orders for the summer quarter
are either less than or equal to the distributor's orders for the spring quarter. But are we concerned about this comparison?
For summer quarter, a special discount would be offered to manufacturer's distributors if their orders for that quarter exceeded those for last year's summer quarter by at least 20 percent. So, we are concerned about such a comparison and that too for the Summer quarter.
But Our conclusion is for the Fall quarter and we are not specifically given in the argument what exact special discount would be offered and what exactly would be the proportion of orders compared to last fall quarter. So, such a comparison is irrelevant. (the argument mentions only this -- the same sort of discount for the fall quarter.)
(B) Along with offering special discounts to qualifying distributors, the manufacturer increased newspaper and radio advertising in those distributors' sales areas.What else the manufacturers did to boost sales for the summer quarter is totally irrelevant to prove a flaw in reasoning for the fall quarter. So, incorrect.
(C) The distributors most likely to qualify for the manufacturer's special discount are those whose orders were unusually low a year earlier.This is talking about the distributors who qualified for the special discount. Again are we concerned for those distributors who qualified OR not qualified?? Does knowing this information will help in anyway to prove a flaw in manufacturer's reasoning for the fall quarter??
The Answer for the above question is YES. We are concerned who qualified and we need to be sure whether they will qualify this FALL Quarter or not.. for increased sales.. But how will this help in proving a flaw??

We need more details. So, Incorrect.
(D) The distributors who qualified for the manufacturer's special discount were free to decide how much of that discount to pass on to their own customers.Totally irrelevant to the context in hand.
(E) The distributors' ordering more goods in the summer quarter left them overstocked for the fall quarter.This proves that in the fall quarter, there will not be enough distributors' ordering goods in the fall quarter as they are overstocked and most of the distributors' who qualified for the special discount will be in the similar condition. This proves that -- Offering discounts for fall quarter may / will not lead to increased sales thus increase in net profits. Hence, this strengthens the mind set with which started looking into the options. Thus, this is the CORRECT ANSWER.