18 Which of the following statements about absorption costing is true? Sales commissions are considered period costs that are included in cost of goods sold under absorption costing O Direct manufacturing costs are expensed in full in the period incurred under absorption costing O Fixed manufacturing overhead cost is considered an inventoriable cost under absorption costing and is therefore included in cost of goods sold expense in the period in which products are sold O Absorption costing is required for internal financial reporting purposes None of the above statements are true