Lawrence Company purchased equipment for $280,000 on January 1, 2017. It is estimated that the equipment will have a useful life of 4 years and a salvage value of $30.000. Estimated production is 50,000 units. Lawrence produces 16,000 units in 2017, 14,000 units in 2018, 12,000 units in 2019, and 10,000 units in 2020. Compute depreciation for each year under each of the following methods. Lawrence is on a calendar-year basis ending December 31. a) Activity method (units of output). b) Sum-of-the-years'-digits method. c) Double-declining balance method