A business operated at 100% of capacity during its first month, with the following results: Sales (120 units) $600,000 Production costs (150 units): Direct materials $75,000 Direct labor 18,750 Variable factory overhead 33,750 Fixed factory overhead 30,000 157,500 Operating expenses: Variable operating expenses Fixed operating expenses 3,360 9,700 The amount of contribution margin that would be reported on the variable costing income statement is Oa. $488,300 Ob. $590,300 Oc. $491,660 Od. $599,850