Evaluation--Computer-based

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.

In order to evaluate the argument, it would be most useful to determine which of the following?

A. Whether the survey collected information about the amount of money respondents spent on free-time media use
B. Whether the amount of time spent watching television is declining among people who report that they rarely or never use computers
C. Whether the type of television programs a person watches tends to change as the amount of time spent per week using computers increases
D. Whether a large majority of the computer owners in the survey reported spending increasing amounts of time per week using computers
E. Whether the survey respondents' reports of time spent using computers included time spent using computers at work

OA: E

can someone explain why B is wrong?
can't figure out why E is better...
thank u!