What is the difference between absorption and variable costing? Select one: a. Absorption costing treats variable manufacturing overhead as a product cost while variable costing treats it as a period cost b. Unlike absorption costing, variable costing can be used under GAAP. c. Absorption costing treats fixed manufacturing overhead as a product cost while variable costing treats it as a period cost. d. Absorption costing is used only for internal analysis, while variable costing can be used for internal and external reporting