Fact: The price has increased. The speed and reliability of service has decreased.
Conclusion: It is mismanaged.
Ask for NOT weakening.
(A) The volume of mail handled by the postal service has increased dramatically over the last forty years.
Increase in volume provide another reason why it is more expensive and slower to get mail, other than mismanagement. Weakens.
(B) Unprecedented increases in the cost of fuel for trucks and planes have put severe upward pressures on postal delivery costs.
Increase in cost offers alternative explaination about why the price is higher. Weakens.
(C) Private delivery services usually charge more than does the postal service for comparable delivery charges.
It says nothing why postal service is worse today then before. NOT weaken.
(D) The average delivery time for a first-class letter four decades ago was actually slightly longer than it is today.
It rebuts the facts upon which the conclusion based, and thus weakens the conclusion.
(E) The average level of consumer prices overall has increased more than 300 percent over the last forty years.
Offers alternative explanation of increase in price other than mismanagement. Weakens.
The OA is E. This makes sense coz 300% = 3 fold but the postal service costs went up by 10 fold.
But now the question is why does C, D not weaken the argument. I see why/how C weakens the argument [see my explanation].
But why is D wrong. To weaken a conclusion, one shouldnt "refute" the premise upon which the argument is based. You bring outside information that weakens the author's assumption.
Can someone explain why "D" weakens the conclusion. I dont see how.
Hmmm I disagree with the OA. Sure 3 fold is not 10 fold but it offers a partial explanation. It doesn't totally overturns the argument, but weakens it. (If 3 fold doesn't weaken, will 5 fold weaken it? 8 fold? Where is this magic point? I'd say as long as the overall price increases it weakens the argument to a certain degree.)
D also weakens the argument about mismanagement because it weakens one of the fact that the argument relies upon.
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