Tirrt Corporation has provided the following Information Direct materials Direct labor Variable manufacturing overhead Fixed manufacturing overhead Sales commissions Variable administrative expense Fixed selling and administrative expense Cost per Unit Cost per Period $7.55 $3.95 $1.60 $24,500 $1.10 $ 8,900 If the selling price is $28.20 per unit, the contribution margin per unit sold is closest to: 1 0 0 0 0