A machine with a cost of $66,914 has an estimated residual value of $5,794 and an estimated life of 4 years or 17,644 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 3,712 hours? Do not round your intermediate calculations. a. $14,077.58 b. $12,858.62 c. $15,280.00 d. $30,560.00