Equipment with a cost of $88,541, an estimated residual value of $4,101, and an estimated life of 13 years was depreciated by the straight- line method for 5 years. Due to obsolescence, it was determined that the remaining useful life should be shortened by 4 years and the residual value changed to zero. The depreciation expense for the current and future years is a. $4,312.62 b. $6,229.34 Oc. $14,016.02 d. $32,476.92