Obama Company sells its product for $25 per unit. During 2012, it produced 20,000 units and sold 15,000 units (there was no beginning inventory). Costs per unit are: direct materials $5, direct labour $4, and variable overhead $3. Fixed costs are: $300,000 manufacturing overhead, and $50,000 selling and administrative expenses. The per unit manufacturing cost under variable costing is

a) $12.

b) $27.

c) $29.50.

d) $32.