question content area a machine with a cost of $120,000 has an estimated residual value of $15,000 and an estimated life 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 full year, during which the machine was used 5,000 hours? a.$45,000 b.$35,000 c.$5,000 d.$21,000