Over the course of a year, Retail Marketers, Inc., sells goods from its inventory and one of its warehouses. In exchange, Retail receives checks and other items that substitute for cash, which Retail uses to repay a loan from Savings Bank. Article $2$ of the UCC governs

a$.$the checks.

b$.$the sale of the goods.

c$.$the payment of the loan.

d$.$the sale of the buildings.