Rexford Corporation produces three products, with costs and selling prices as follows: Product A Product B Product C Machine hours per unit 500 units 500 $30 $20 Maximum demand units 500 units Selling price per unit $15 Variable costs per unit $ 6 Contribution Margin per unit $ 9 $18 $15 $12 Machining is the bottleneck. Total machine time available is 2,100 hours. What is the maximum contribution margin that Rexford can earn by optimal use of the constrained resource? $18.700 $5.300 $11,500 59.400