18. Trux Corporation produces a single product. Last year, the company had net operating income of $100,000 using variable costing. Beginning and ending inventories were 13,000 units and 18,000 units, respectively. If the fixed manufacturing overhead cost was $4 per unit both last year and this year, what would have been the net operating income using absorption costing? A) $80,000 B) $100,000 C) $120,000 D) $172,000