Cullumber Corporation purchased a new machine for its assembly process on August 1, 2017. The cost of this machine was $172,134. The company estimated that the machine would have a salvage value of $18,834 at the end of its service life. Its life is estimated at 5 years, and its working hours are estimated at 23,000 hours. Year-end is December 31. Compute the depreciation expense under the following methods. Each of the following should be considered unrelated. (Round depreciation rate per hour to 2 decimal places, e.g. 5.35 for computational purposes. Round your answers to 0 decimal places, e.g. 45,892.)

a.) Straight-line depreciation for 2017

b.) Activity method for 2017, assuming that machine usage was 850 hours

c.) Sum-of-the-years'-digits for 2018

d.)Double-declining-balance for 2018