GMAT Critical Reasoning (CR) | Re: A survey was recently conducted among ferry passengers on the North

A survey was recently conducted among ferry passengers on the North Sea. Among the results was this: more of those who had taken anti-seasickness medication before their trip reported symptoms of seasickness than those who had not taken such medication. It is clear, then that despite claims by drug companies that clinical tests show the contrary,people would be better off not taking anti-seasickness medications .

Which one of the following, if true, would most weaken the conclusion above?

(A)
...

---