A business operated at 100% of capacity during its first month and incurred the following costs: Production costs (20,000 units): Direct materials $180,000 Direct labor 240,000 Variable factory overhead 280,000 Operating expenses: Variable operating expenses $130,000 Fixed operating expenses 50,000 180,000 Tf 1,600 units remain unsold at the end of the month, the amount of inventory that would be reported on the variable costing balance sheet is a. $64,000 b. $56,000 c. $66,400 d. $78,400