A machine with a cont of $120.000 has an estimated residual value of $15,000 and an estimated te of 5 years or 15,000 hours. It is to be depreciated by the units-of-output method. What is the amount of depreciation for the second ful year, during which the machine was used 6,000 hours? $35,000 $5,000 $21.000 $45,000