DEF Inc. has an assembling machine with a useful life of eight years. The original cost was $43,000 and the residual value is $3,000. If DEF uses sum-of-the-years'-digits for its depreciation method, what is depreciation expense in year two, assuming the asset is put in service January 1? When calculating the depreciation rate, round the calculated result to two decimal places (e.g., .10). Choose one answer. a. $7,600 b. $8,170 c. $6,500 d. $7,100