Answer:
A. money-back guarantee
Step-by-step explanation:
Money-back guarantee represents when buyers purchase a product from the market and get a warranty card. After purchasing a product if the buyer is not satisfied with the product and goes to the shop by stating that he is not satisfied with the product and it comes under warranty. The Product can replace a product or money-back guarantee (if it comes under the policy when purchased the product) if the customer not satisfied with the product.
So if seller is promised from buyer for a money-back guarantee if buyer is not satisfied from the product then the seller has a responsibility to return the buyer money.