of On April 1, 2024, a machine was purchased for $33,600. It was estimated that it would have a $3,200 residual value at the end of its five-year useful life. It was also estimated that the machine would be used for a total of 80,000 hours over the five years. If the actual number of machine hours used in 2024 was 12,000 hours and the company uses the units-of-production method of depreciation, the depreciation expense for 2024 would be O a. $5,040. O b. $4,560. O C. $3,420. O d. $3,780