On January 1, 20x2, Astro Ltd. purchased a piece of equipment costing $79756. At the time, the equipment's useful life was expected to be 9 years with an estimated residual value of $15778. In 20x6, these estimates were revised: the total estimated useful life of the equipment is expected to be 14 years and the residual value is expected to be $8780. What will the depreciation expense be for 20x6? Assume the company uses straight-line depreciation. Select one: a. $4254 b. $3039 c. $7109 d. $3543