Dynondo's Brakes 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 Medel z Selling price $70 Direct materials 6 6 6 Direct labor ($17 per hour) 17 17 34 Variable support costs (54 per machine-hour) 4 11 8 Fixed support costs 11 11 How can Lisa Dynondo encourage her salespeople to promote the more profitable model? Put all sales persons on fixed salary. Provide higher sales commissions for items which has the lowest cost and lower sales commissions for items with highest cost. Provide higher sales commissions for items with the greatest contribution margin per constrained resource. Provide higher sales commissions for higher priced items