Manning Industries manufactures and sells three different models of wet-dry shop vacuum cleaners. Although the shop vacs vary in terms of quality and features, all are good sellers. Manning is currently operating at full capacity with limited machine time. Sales and production information relevant to each model follows. Product Economy Standard Deluxe Selling price $30 $50 $100 Variable costs and expenses $12 $18 $42 Machine hours required .5 .8 1.6 Instructions (a) Ignoring the machine time constraint, which single product should Manning Industries produce? (b) What is the contribution margin per unit of limited resource for each product? (c) If additional machine time could be obtained, how should the additional time be used