Shelling Company owns $30,000 of manufacturing equipment. The equipment has a 10-year useful life and a $6,000 salvage value. Shelling uses straight-line depreciation. During the most recent annual accounting period the company made 1, 200 units of product. Assuming Shelling sold 1,000 units of product, the amount of depreciation that would be included in cost of goods sold is: a. zero. b. $3,000 c. $2, 500 d. $2,000