Equipment with a cost of $220,000 has an estimated residual value of $30,000 and an estimated life of 10 years or 19,000 hours. It is to be depreciated by the straight-line method. What is the amount of depreciation for the first full year, during which the equipment was used for 2,100 hours? a. $21,000 b. $22,000 c. $19,000 d. $30,000