An argument claims: 'Sales of our new eco-friendly cleaning product increased significantly in the last quarter. This indicates a growing consumer preference for sustainable options.' Which of the following, if true, would best strengthen the argument's conclusion?

The correct answer to the question "An argument claims: 'Sales of our new eco-friendly cleaning product increased significantly in the last quarter. This indicates a growing consumer preference for sustainable options.' Which of the following, if true, would best strengthen the argument's conclusion?" is Option A: Competitors' sales of non-eco-friendly products decreased during the same period..

The other options — B) A recent survey showed 80% of consumers are willing to pay more for sustainable products., C) Our company launched a major advertising campaign for the eco-friendly product last quarter., D) The overall market for cleaning products grew by 5% in the last quarter. — are incorrect for this GMAT Exam Prep question. As explained above: If sales of non-eco-friendly products decreased, it reinforces the idea that consumers are actively shifting towards sustainable options, directly supporting the conclusion of growing preference.