Carver Company produces a product that sells for $30. Variable manufacturing costs are $15 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 10% of the selling price is paid on each unit sold. What is the contribution margin per unit?

• $3.

• $15.

• $8.

• $12.