题目选项分析

To reduce the danger to life and property posed by major earthquakes, scientists have been investigating several techniques for giving advance warning of dangerous earthquakes. Since catfish swim erratically before earthquakes, some investigators have proposed monitoring catfish to predict dangerous earthquakes.

Which of the following, if true, most seriously undermines the usefulness of the proposal?

【选项】Even very slight, fleeting tremors cause catfish to swim erratically.