Oats Company Offers a Trade Discount to Its Customers as a Reward

Oats Company offers a trade discount to its customers as a reward for large orders. According to the International Accounting Standards Board (IASB) how should the customers of Oats Company account for these trade discounts?

A) As an expense.
B) As a revenue.
C) As a reduction in the cost of inventory.
D) The IASB allows any of these treatments so long as the company applies it consistently.