What factor is the cause of the difference between operating income computed using absorption costing and operating income computed using variable costing? 58 Multiple Choice O Absorption costing allocates fixed manufacturing costs between cost of goods sold and inventories, and variable costing considers all fixed manufacturing costs as period costs. O Absorption costing includes all variable manufacturing costs in product costs, but variable costing considers variable manufacturing costs to be period costs. Absorption costing includes all fixed manufacturing costs in product costs, but variable costing expenses all fixed manufacturing costs O Absorption costing considers all manufacturing costs in the determination of operating income, whereas variable costing considers only prime costs