Sammie's Pizza sells an average of 150 pizzas per​ week, of which 20​% are​ single-topping pizzas and 80​% are supreme pizzas with multiple toppings. Singles sell for $ 8 each and incur variable costs of $ 2. Supremes sell for $ 12 each and incur variable costs of $ 6. Which pizza should Sammie's Pizza promote to maximize​ profits? A. Singles because they contribute the highest total contribution margin. B. Supremes because they have the highest contribution margin ratio. C. Both should be promoted equally because they have the same contribution margin per unit. D. Singles because they have the highest contribution margin ratio.