Trent Department Store uses a perpetual inventory system but adjusts its inventory records at year-end to reflect the results of a complete physical inventory. In the physical inventory taken at the end of 2015 and 2016 , Trent's employees failed to count the merchandise in the store's window displays. The cost of this merchandise amounted to $13,000 at the end of 2015 and $19,000 at the end of 2016. As a result of these errors, the cost of goods sold for 2016 will be: a. Understated by $19,000 b. Overstated by $6,000 c. Understated by $6,000 d. Overstated by $19,000