Among the options provided, 3 a coupon clip from a newspaper is the best example of a positive incentive for consumers. Coupons serve as a direct financial benefit, encouraging consumers to purchase products by offering discounts. This kind of incentive promotes savings and can influence consumer behavior by making products more affordable.
On the other hand, the other options represent different economic concepts that do not specifically motivate consumer spending in a positive way. A sales tax (option 1) typically increases the cost of goods, which may deter spending. A steady rise in profits (option 2) is more related to business performance rather than consumer incentive. Finally, an increase in price for a popular product (option 4) could discourage buyers due to higher costs. Therefore, the coupon is the clear positive incentive that encourages purchasing.