The official explanation is too huge to post here. You can find it
hereThe reasoning for selection between the answer choices is as follows:
A: This option is incorrect. Suppose the print circulation of the newspaper would have declined further in the near future. Then, the perception that the Print Mode is a sinking business would be further strengthened and the newspaper's decision to kill the Print Mode would be validated. So, if we Negate this answer choice, the conclusion (= decision made by the newspaper) stands strengthened, instead of being demolished. Therefore, this answer choice fails the Negation Test.
B: This option is incorrect. Let the revenue that the print edition of the newspaper earned per reader each month (at the time of the decision) be dollars. Suppose the readers of the newspaper's website are not willing to pay a subscription fees of dollars per month for access to the website content. Does this necessarily mean that the newspaper will not be able to maintain its profits? No. For example, suppose the readers of the website are only willing to pay a monthly subscription fees of dollars. If the number of website readers is more than ten times the number of print-edition readers (which it very well might be, because, from the argument, we only know the percentage changes in readership of the print-edition and the website traffic, and not the actual numbers), then the revenue from the website subscription fees will be greater than the revenue from the print-edition. If the costs of the website are not greater than the costs of the print-edition, then the profits from the website will be greater than the profits that the print-edition earned at the time of the decision. Therefore, negating this answer choice does not necessarily impact the conclusion.
C: This option is incorrect. Suppose the print circulation did not decline in the past two years because of the content offered in the Web Mode but due to some other reason. The facts of the case still remain the same – the print circulation was declining, the Web Mode traffic was increasing, and the newspaper wanted to maintain its profits. So, negating this answer choice has no impact whatsoever on the conclusion drawn.
D: This option is incorrect. Suppose the revenue earned from increased website traffic is indeed less than the revenue lost by discontinuing the print edition. However, if the costs incurred by the newspaper for the Web Mode are far lesser than those for the Print Mode, then profits earned by the newspaper for the Web Mode can still be greater than or equal to the profits earned for the Print Mode. Therefore, the conclusion ("to maintain profits," kill the Print Mode and put more of XYZ type of traffic-increasing content on the Web Mode) can still stand. Therefore, this answer choice fails the Negation Test.
E: This option is correct. Suppose that introducing more content similar to the exclusive content on the most read pages of the website will not increase the newspaper's website traffic further. The newspaper had assumed: (More such content --> More Web Traffic --> More Profit from Web-Mode that would at least offset the loss of profit from Print-mode). The negation of this answer choice breaks this chain of assumptions and therefore suggests that the newspaper's decision may not result in greater profit from Web-Mode that would at least offset the loss of profit from Print-Mode. Therefore, the profits of the newspaper may not be maintained. The negation of this answer choice substantially weakens the decision made by the newspaper. Therefore, this answer choice represents a necessary assumption on which this decision depends.
Correct answer is E.