Equipment with a cost of $83,647, an estimated residual value of $5,994, and an estimated life of

10 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

Oa. $3,705.52

Ob. $4,117.24

Oc. $37,055.20

Od. $46,591.80