Critical Reasoning

Because it was long thought that few people would watch lengthy televised political messages, most televised political advertisements, like commercial advertisements, took the form of short messages. Last year, however, one candidate produced a half-hour-long advertisement. During the half hour the advertisement was aired, a substantial portion of the viewing public tuned into the advertisement. Clearly, then, many more people are interested in watching lengthy televised political messages than was previously thought.
Which of the following is an assumption on which the argument depends?
A. The candidate’s ratings improved significantly as a result of the half-hour-long political advertisement.
B. Political advertisements have become increasingly influential in determining voters’ decisions at the polls.
C. Many people would appreciate the opportunity to become better acquainted with political candidates’ views on current political issues.
D. Most people who are interested in political issues watch television regularly.
E. Most of the viewers who tuned in to the candidate’s half-hour-long advertisement last year did not change channels after the first few minutes.