题目选项分析

Advertisement: Ten years ago, the Cormond Hotel's lobby was carpeted with Duratex carpet while the lobby of a nearby hotel was being carpeted with our competitor's most durable carpet. Today, after a decade in which the two hotels have had similar amounts of foot traffic through their lobbies, that other hotel is having to replace the worn-out carpeting near its lobby entrances, whereas the Cormond's Duratex carpeting has years of wear left in it.

Which of the following, if true, most seriously weakens the force of the advertisement's evidence for concluding that Duratex carpet is more durable than the carpet of its competitor?

【选项】There is a third hotel near the other two that has not replaced the Duratex carpet in its lobby for more than 15 years.