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 $71 $69 Selling price Direct materials Direct labor ($13 per hour) Variable support costs ($5 per machine - hour) Fixed support costs Which model has the greatest contribution margin per unit? O A. Model X OB. Model Y O C. Model z OD. Both Model X and Model Y have the highest and same contribution margin per unit