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Ring Company sells several products. Information of average revenue and costs is as follows: Selling price per unit $32.00 Variable costs per unit: Direct material $5.25 Direct manufacturing labor $2.50 Manufacturing overhead $0.30 Selling costs $2.25 Annual fixed costs $115,000 The company sells 11,000 units. The contribution margin per unit is: O $11.25 O $21.70 O $23.95 O $24.25