A business operated at 100% of capacity during its first month, with the following results: Sales (112 units) $560,000 Production costs (140 units): Direct materials $70,000 Direct labor 17,500 Variable factory overhead 31,500 Fixed factory overhead 28,000 147,000 Operating expenses: Variable operating expenses Fixed operating expenses $6,220 3,350 9,570 The amount of contribution margin that would be reported on the variable costing income statement is Oa. $455,230 Ob. $559,860 Oc. $550,430 Od. $458,580