Willis Company had a operating profit of 75,000 using variable costing and a operating profit of 57,000 using absorption costing. Variable production costs were 15 per unit. Total fixed manufacturing overhead was 120,000 and 10,000 units were produced. During the year, the inventory level

increased by 1,200 units.

increased by 1,500 units.

decreased by 1,500 units.

decreased by 1,200 units.