Carver Corporation Produces a Product Which Sells for $40

Carver Corporation produces a product which sells for $40.Variable manufacturing costs are $18 per unit.Fixed manufacturing costs are $5 per unit based on the current level of activity,and fixed selling and administrative costs are $4 per unit.A selling commission of 15% of the selling price is paid on each unit sold.The contribution margin per unit is:

A) $7
B) $17
C) $22
D) $16