A machine with a cost of $209,000 has an estimated residual value of $19,000 and an estimated life of 4 years or 19,000 hours. It is to be depreciated by the units-of-activity method. What is the amount of depreciation for the second full year, during which the machine was used 6,000 hours? a. $72,000 b. 560,000 c. $41,000 A. 56,000