Which of the following statements about the double - declining - balance (DDB) method is true? OA. Companies that use the DDB method generally do not use scrap value to calculate current-year depreciation expense, except in the last year of an asset's OO B. Using the DDB method, the amount of depreciation expense varies from year to year depending on usage of the asset. C. Companies that use the DDB method do not use partial-year depreciation. OD. All of the above statements are true