Equipment with a cost of $72,826, an estimated residual value of $5,579, and an estimated life of 12 years was depreciated by the straight-line method for 6 years. Due to obsolescence, it was determined that the remaining useful life should be shortened by 3 years and the residual value changed to zero. The depreciation expense for the current and future years is

a. $33,623.50

b. $3,266.88

c. $4,355.83

d. $13,067.50