10) Which of the following costs at a manufacturing company would be treated as a product cost under variable costing? A) direct material cost B) property taxes on the factory building C) sales manager's salary D) sales commissions 11) The costing method that treats all fixed costs as period costs is: A) absorption costing. B) job-order costing. C) variable costing. D) process costing. 12) Which of the following is true of a company that uses absorption costing? A) Net operating income fluctuates directly with changes in sales volume. B) Fixed production and fixed selling costs are considered to be product costs. C) Unit product costs can change as a result of changes in the number of units manufactured D) Variable selling expenses are included in product costs