Williamson Corporation purchased a depreciable asset for 300,000 on January 1, 2016. The estimated residual value is 30,000, and the estimated useful life is 9 years. The straight-line method is used for depreciation. In 2019, Williamson changed its estimates to a total useful life of 5 years with a salvage value of 50,000. What is 2019 depreciation expense? a. 30,000 b. 50,000 c. 80,000 d. 90,000