GMAT Critical Reasoning (CR) | Re: Market resaerchers recently reported that ninety percent of

Option B is one of the assumptions needed to reach the conclusion. Hence, it is the answer here. But another fundamental assumption the author relies upon while
drawing the conclusion is that the consumers who object to the detergent's advertisement do not buy the detergent. Because otherwise we might have more that 80 %
of consumers who object to the advertisement but still buy the detergent and this weakens the conclusion..

Guys any thoughts on this.