Consider the following information with respect to the manufacture of one unit of output: 1 direct labor hour is required to produce the unit; the selling price is $20 per unit; the variable costs are $10 per unit; the direct materials cost is $2 per unit. Which of the following is true? The contribution margin earned per direct labor hour used in the production of one unit is the same as the contribution margin earned from the sale of one unit. If direct labor is a constraint and the amount of direct materials available for production is unlimited, then the number of units produced can be maximized. The contribution margin earned per direct labor hour used in the production of one unit cannot be determined. The contribution margin from the sale of one unit cannot be determined