Happy Manufactures acquired a machine at the beginning of 2020 for RM200,000.It has an estimated life of five years, 20,000 productive hours,or 25,000 units. The estimated residual value is RM10,000. During the year ended 31 December 2020, the machine was used for 3,000 productive hours to produce 3,500 units of output. Required: Calculate the depreciation expense using the following depreciation methods: a) Straight-line (b) Sum of digits methoa (c) Units of output (d) Productive hours