A business operated at 100% of capacity during its first month, with the following results: Sales (96 units) $480,000 Production costs (120 units): Direct materials $60,000 Direct labor 15,000 Variable factory overhead 27,000 Fixed factory overhead 24,000 126,000 Operating expenses: Variable operating expenses $6,380 Fixed operating expenses 4,130 10,510 What is the amount of the contribution margin that would be reported on the variable costing income statement? a. $387,890 b. $392,020 c. $479,880 d. $469,490