On January 2, 2018, Country Lumber Installed a computerized machine in its factory at a cost of $168,000. The machine's useful life was estimated at four years or a total of 190,000 units with a $35,000 trade-in value. Country Lumber's year-end Is December 31. Calculate depreciation for each year of the machine's estimated useful life under each of the following methods: a. Straight-line b. Double-declining-balance c. Units-of-production, assuming actual units produced were: Year Units 2018 39,900 2019 43,550 2020 54,200 2021 72,000 Year 2018 2019 2020 2021 Total a. Straight- b. Double-Declining- c. Units-of- Production Line Balance