NOI under absorption costing was $50,000, based on 25,000 units sold. The company had produced 35,000 units and had zero beginning inventory. Fixed overhead cost was $4/unit, and variable overhead cost was $3/unit. The sum of direct materials and direct labor per unit was $10/unit. What is the NOI under variable costing? a. $10,000 b. $20,000 c. $90,000 O d. -$20,000