Damascus Moving Limited purchased a van for moving customers on January 1, 2019 for $28,000. Management expects to be able to sell the van for $2.000 at the end of its useful life and estimates the var's useful life to be 5 years or 100,000 km. The van was driven 18,000km in 2019, 22,000 km in 2020 8219,000 km in 2021 Required: Calculate the depreciation expense for 2019, 2020 2021 using: a. the double declining balance method the straight-line method c the units of production method