Answer:
Sales allowance.
Step-by-step explanation:
From the question we are informed about Gershwin Wallcovering Inc. shipped the wrong shade of paint to a customer. The customer agreed to keep the paint upon being offered a 15% price reduction. In this case, The price reduction is an example of a Sales allowance.
Sales allowance can be regarded as a reduction in the price that was charged by a seller, this reduction usually occur due to a problem with the product or service that is been sold. The problem could be incorrect price as well as quality problem or short shipment.