Glass Company manufactures three different product lines, Model TS, Model AY, and Model GG. Considerable market demand exists for all models. The following per unit data apply: Model TS AY GG Selling price $100 $120 $140 Direct materials 12 12 12 Direct labor ($12 per hour) 24 24 48 Variable support costs ($4 per machine-hour) 8 16 16 Fixed support costs 20 20 20 Which model has the greatest contribution margin per unit