Steuben Company produces dog houses. During the current year, Steuben Company incurred the following costs: Rent on manufacturing facility Office manager's salary Wages of factory machine operators Depreciation on manufacturing equipment Insurance and taxes on selling and administrative offices Direct materials purchased and used $250,000 150,000 110,000 50,000 30,000 170,000 Based on the above information, which of the following would not be treated as a product cost: Office manager's salary Rent expense incurred on manufacturing facility Depreciation on manufacturing equipment Wages of factory machine operators