Department A had 4,900 units in work in process that were 71% completed as to labor and overhead at the beginning of the period, 36,500 units of direct materials were added during the period, 39,400 units were completed during the period; and 2,000 units were 31% 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.41,400

b.39,400

c.36,500

d.34,500