Costner Company uses an absorption costing system in accountingfor the single product it manufactures. The following selected data are for the year2009:

Sales (10,000 units) $360,000 Direct materials used (variable cost) 129,600 Direct labor costs (variable cost) 43,200 Variable manufacturing overhead 12,960 Fixed manufacturing overhead 17,280 Variable selling and administrative expenses 21,600 Fixed selling and administrative expenses 72,000 The company produced 12,000 units and sold 10,000 units. Direct materials anddirect labor are variable costs. One unit of direct material goes into each unit offinished goods. Overhead rates are based on a volume of 12,000 units and are USD1.08 and USD 1.44 per unit for variable and fixed overhead, respectively. The ending inventory is the 2,000 units of finished goods on hand at the end of 2009. There was no inventory at the beginning of 2009. a. Prepare an income statement for 2009 under variable costing. b. Prepare an income statement for 2009 under absorption costing. c. Explain the reason for the difference in net income between a and b