Springer Products manufactures three different product lines, Model X, Model Y, and Model Z. Considerable market demand exists for all models. The following per unit data apply: Model X Model Y Model Z Selling price $ 54 $ 65 $ 73 Direct materials 8 8 8 Direct labor ($ 16 per hour) 16 16 32 Variable support costs ($ 5 per machineminushour) 5 10 10 Fixed support costs 13 13 13 Which model has the greatest contribution margin per unit?