1. 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 company's 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