Final answer:
The advantage of sales promotion that is not guaranteed is repeat customers.
Step-by-step explanation:
The correct answer is d) guarantees repeat customers. This is not one of the advantages of sales promotion. Sales promotion techniques such as discounts, coupons, and loyalty programs can help attract new customers and encourage repeat purchases, but they cannot guarantee repeat customers.
The effectiveness of sales promotion in generating repeat business depends on various factors such as the quality of the product or service, customer satisfaction, and overall marketing strategy.