Indicate whether each of the following costs should be classified as a product cost or as an SG&A cost in accordance with GAAP. a. Wages paid to workers in a manufacturing plant. b. The salary of the receptionist working in the sales department. c. Supplies used in the sales department. d. Wages of janitors who clean the factory floor. e. The salary of the company president. f. The salary of the cell phone manufacturing plant manager. g. The depreciation on administrative buildings. h. The depreciation on the company treasurer's computer. i. The fabric used in making a customized sofa for a customer. j. The salary of an engineer who maintains all manufacturing plant equipment