What is the observed effect the author is trying to explain? " . . . the share of the population that reads a daily newspaper has declined greatly in the past 20 years."
The author's explanation for this observed effect? "Clearly, increased television viewing has caused a simultaneous decline in newspaper reading."
Notice that the author is taking a correlation (decrease in reading newspaper, increase in watching television) and concluding a cause and effect relationship.
This is a Weaken question as we are looking for the answer choice that "would be most damaging to explanation given above for the decline in newspaper reading."
The problem with (E) is that just because a typical TV set is on 6 hours a day, which is down from an average of 6.5 hours a day 5 years ago, doesn't change the fact that the "percentage of the population that watches television daily has shown a similarly dramatic increase over the same period."
So (E) is completely irrelevant.
Hope that helps! Please let us know if you have any other questions.
