Aurum Appliances manufactures three sizes of kitchen appliances: small, medium, and large. Product information is provided below. Medium $640 Small $430 Large $1230 Unit selling price Unit costs: (500) (280) (130) $320 (220) (120) (80) $10 (280) (140) (85) $135 Variable manufacturing Fixed manufacturing Fixed selling and administrative Unit profit 150 130 150 Demand in units 150 40 40 Machine-hours per unit The maximum machine-hours available are 6500 per week. What is the contribution margin per machine-hour for a medium appliance? $12.63 $9.00 $3.38 $1.04