Carver Company Produces a Product That Sells for $30

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. The contribution margin per unit is?

A) $3.
B) $15.
C) $8.
D) $12.