Department A had 4,000 units in work in process that were 63% completed as to labor and overhead at the beginning of the period, 32,100 units of direct materials were added during the period, 33,100 units were completed during the period; and 3,000 units were 20% 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 period was a. 29,100 b. 33100 c. 36,100 d. 32.100