Manufacturers issue cents-off coupons to get consumers to try their brand of product with the hope that the consumers who try their brand will switch their brand loyalty. So in the initial marketing of their new brand X, Hartman Industries should issue cents-off coupons, thereby attracting a large segment of potential consumers as loyal customers. Which of the following, if true, casts the most serious doubt on the likelihood that the marketing strategy recommended above will have the result that is claimed? ['A marketing campaign that uses cents-off coupons is most effective when combined with a television advertising campaign.', 'Typically less than one-third of the coupons issued by a manufacturer are redeemed by consumers.', "Many grocery stores attract customers by doubling the face value of manufacturer's coupons.", 'The consumers whose purchases are strongly influenced by cents-off coupons tend not to become loyal customers of any particular brand.']