If variable manufacturing costs are $9 per unit and total fixed manufacturing costs are $626,400, what is the manufacturing cost per unit ifa.7,200 units are manufactured and the company uses the variable costing concept?$b.8,700 units are manufactured and the company uses the variable costing concept?$c.7,200 units are manufactured and the company uses the absorption costing concept?$d.8,700 units are manufactured and the company used the absorption costing concept?