Stephen Company produces a single product. Last year, the company had 20,000 units in its ending inventory. During the year, Stephen's variable production costs were $12 per unit. The fixed manufacturing overhead cost was $8 per unit in the beginning inventory.

The companys net operating income for the year was $9,600 higher under variable costing than it was under absorption costing. The company uses a last-in-first-out (LIFO) inventory flow assumption. Given these facts, the number of units of product in the beginning inventory last year must have been: A) 21,200 B) 19,200 C) 18,800 D) 19,520