A. Under variable costing, the variable costs of production are inventoried while the fixed manufacturing costs are expensed as incurred. The variable costs of production include the prime costs (direct labor and direct materials) and variable manufacturing overhead. In total, this is $900,000.

B. This answer does not include variable manufacturing overhead, which is inventoried under variable costing.

C. This answer includes fixed manufacturing overhead, which is not inventoried under variable costing.

D. This answer includes variable selling and other expenses which are not included in inventoriable costs under the variable method because they are not production costs.