Robert Parish Corporation purchased a new machine for its assembly process on August 1, 2020. The cost of this machine was $117,900. The company estimated that the machine would have a salvage value of $12,900 at the end of its service life. Its life is estimated at 5 years, and its working hours are estimated at 21,000 hours. Year-end is December 31. Instructions Compute the depreciation expense under the following methods. Each of the following should be considered unrelated. a. Straight-line depreciation for 2020. b. Activity method for 2020, assuming that machine usage was 800 hours. c. Sum-of-the-years'-digits for 2021. d. Double-declining-balance for 2021