Ross Corporation Produces a Single Product

Ross Corporation produces a single product. The company has direct materials costs of $8 per unit, direct labor costs of $6 per unit, and manufacturing overhead of $10 per unit. Sixty percent of the manufacturing overhead is for fixed costs. In addition, variable selling and administrative expenses are $2 per unit, and fixed selling and administrative expenses are $3 per unit at the current activity level. Assume that direct labor is a variable cost.
-Under variable costing,the unit product cost is:

A) $24 per unit
B) $20 per unit
C) $18 per unit
D) $21 per unit