Assume operating income under absorption costing is $500 during the period. Using the information given, do income reconciliation to find income under variable costing. Beginning inventory 20 units Production 50 units Sales 40 units Direct materials $15 per unit Direct manufacturing labor $30 per unit Variable manufacturing costs $ 6 per unit Variable marketing costs $10 per unit Fixed manufacturing costs $300 in total Fixed administrative costs $150 in total a) $490 b) $440 c) $530 d) $560