B Company switched from the sum-of-the-years-digits depreciation method to straight-line depreciation in 2021. The change affects machinery purchased at the beginning of 2019 at a cost of $81,300. The machinery has an estimated life of five years and an estimated residual value of $4,065. What is B's 2021 depreciation expense? Multiple Choice $21,680. $15,447 $10,298