Equipment with a cost of $74,325, an estimated residual value of $6,860, and an estimated life of 14 years was deprecated by the straight-line method for 7 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 Oa. $3,69023 Ob. 52,89946 Oc. 533.732.50 Od. 513,530,53