题目选项分析

Advertisement:

For sinus pain, three out of four hospitals give their patients Novex. So when you want the most effective painkiller for sinus pain, Novex is the one to choose.

Which of the following, if true, most seriously undermines the advertisement's argument?

【选项】In clinical trials Novex has been found more effective than competing brands of painkillers that have been on the market longer than