Department A had 4,700 units in work in process that were 66% completed as to labor and overhead at the beginning of the period, 33,900 units of direct materiais were added during the period, 36,000 units were completed during the period, and 2,600 units were 25% completed as to labor and overhead at the end of the period. All materials are added at the beginning of the process. The first-in, first-out method is used to cost inventories. The number of equivalent units of production for material costs for the penod was a. 31,300 b. 35.600 c. 33.000 d. 36,000