Grove Co. acquired a production machine on January 1, 2019, at a cost of $570,000. The machine is expected to have a four-year useful life, with a salvage value of $116,000. The machine is capable of producing 86,000 units of product in its lifetime. Actual production was as follows: 18,920 units in 2019; 27,520 units in 2020; 24,080 units in 2021; 15,480 units in 2022. Following is the comparative balance sheet presentation of the net book value of the production machine at December 31 for each year of the asset's life, using three alternative depreciation methods (items a-c): Required: Identify the depreciation method used for each of the following comparative balance sheet presentations (items a-c). If a declining- balance method is used, be sure to indicate the percentage (150% or 200%). (Hint: Read the balance sheet from right to left to determine how much has been depreciated each year. Remember that December 31, 2019, is the end of the first year.) Production Machine, Net of Accumulated Depreciation At December 31 Depreciation Method 2022 2021 2020 2019 a. 324,840 b. 116,000 116,000 116,000 197,720 116,000 229,500 142,500 470, 120 285,000 456,500 C. 343,000