题目选项分析

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. At the beginning of the half-hour slot a substantial portion of the viewing public had tuned in to that station. Clearly, then, many more people are interested in lengthy televised political messages than was previously thought.

Which of the following, if true, most seriously weakens the argument?

【选项】The half-hour-long advertisement was aired during a time slot normally taken by one of the most popular prime-time shows.