Aaker Corporation, which has only one product, has provided the following data concerning its most recent month of operations: $99 Units in beginning inventory Units sold. Units in ending inventory 6,300 6,000 300 Variable costs per unit $12 $42 $6 $6 Direct materials Direct labor... Variable manufacturing overhead Variable selling and administrative. Fixed costs: Fixed manufacturing overhead... Fixed selling and administrative.. ..$170,100 $24,000 What is the net operating income for the month under variable costing? $8,100 - $3,900 $12,000 $(14,100)