The growing popularity of computer-based activities was widely expecte

The growing popularity of computer-based activities was widely expected to result in a decline in television viewing, since it had been assumed that people lack sufficient free time to maintain current television-viewing levels while spending increasing amounts of free time on the computer. That assumption, however, is evidently false: in a recent mail survey concerning media use, a very large majority of respondents who report increasing time spent per week using computers report no change in time spent watching television.

First step, Read the question stimulus very carefully,
Which of the following would it be most useful to determine in order to evaluate the argument?

Second step, deconstruct the argument in yours words:
rise the computer-based activities result in a decline in television viewing, but why?
it is assumed that people use more free time on the computer rather than spending television viewing,
The above assumption is false, but why? A recent survey related to media use found that a large majority
of respondents who report increasing time spent per week using computer report no change in time spent watching television

Third Step: find the conclusion of the argument
Conclusion: The above assumption is false. a recent survey is just to support the author's claim.
Fouth Step: Wrong to Right
What if respondents lie about their time spent on the computer per week(maybe more on watching television or the same amount of time spent on both)
What if respondents spent their time on other activities more than a computer? let's see the option choices
Fifth Step: Read each option choice very clearly and precisely

(A) Whether a large majority of the survey respondents reported watching television regularly
we are here concerned about respondents who report increasing time spent. In this option, choices don't clearly say how many hours they spent on watching
television. For example, I daily visit the GMATClub to solve a Verbal OG problem. But it doesn't tell how many hours I spent solving The OG problem
may be one hour or two-hour. similarly, a large majority of the survey respondents don't tell us how many hours they spent watching television
regularly. we can assume any hours here. that's why option choice (a) is wrong.

(B) Whether the amount of time spent watching television is declining among people who report that they rarely or never use computers
it is out of context.

(C) Whether the type of television programs a person watches tends to change as the amount of time spent per week using computers increases
we aren't concerned with the television programs a person watches.

(D) Whether a large majority of the computer owners in the survey reported spending increasing amounts of time per week using computers
spending increasing amounts of time doesn't mean how many hours increase to watching TV. Same as(a)

(E) Whether the survey respondents' reports of time spent using computers included time spent using computers at work
if yes, survey respondents' reports of time spent using computers included time spent using computers at work. It weakens the author's argument.
If No, survey respondents' reports of time spent using computers didn't include time spent using computers at work. it strengthens the argument.