Black Company uses the weighted-average method in its process costing system. The company's ending work in process inventory consists of 5,000 units, 80% complete with respect to materials and 50% complete with respect to labor and overhead. If the total dollar value of the inventory is $60,000 and the cost per equivalent unit for labor and overhead is $8.00, the cost per equivalent unit for materials must be:

A) $5.00 B) $10.00 C) $8.00 D) $4.00