36. The three most common cost behavior classifications are A. fixed costs, variable costs, and mixed costs B. variable costs, sunk costs, and opportunity costs C. variable costs, period costs, and differential costs D. variable costs, product costs, and sunk costs 37. Which of the following costs is a mixed cost? A. electricity costs of $3 per kilowatt-hour B. straight-line depreciation on factory equipment C. rental costs of $10,000 per month plus $0.30 per machine hour of use D. salary of a factory supervisor 38. Given the following cost data, what type of cost is shown? Total Cost Number of units $20 $40 2 $60 3 $80 4 A. variable cost B. period cost C. fixed cost D. mixed cost