Assume a company makes four products (A, B, C, and D) in a single facility. Data concerning these products appear below: Product Product Product Product A B C D Selling price per unit (a) $42.30 $50.00 $37.60 $33.50 Variable manufacturing cost per unit $20.80 $30.70 $21.00 $ 19.90 Variable selling cost per unit 2.70 2.10 1.00 2.40 Milling machine minutes per unit 3.30 4.10 2.60 1.30 Monthly demand in units 1,000 4,000 3,000 3,000 The milling machines are the constraint in the production facility. A total of 14,000 minutes are available per month on these machines. Which of the four products has the highest contribution margin per unit of the constraining resource? Product D Product A Product C Product B