Doe, Inc. purchased a bulldozer at a cost of $300,000. The bulldozer has an estimated residual value of $20,000 and an estimated life of 10 years, or 15,000 hours of operation. The bulldozer was purchased on January 1, 2020 and was used 500 hours in 2020 and 3,000 hours in 2021. What method of depreciation will produce the maximum depreciation expense in 2021