Department A had 4,400 units in work in process that were 65% completed as to labor and overhead at the beginning of the period; 26,600 units of direct materials were added during the period; 28,200 units were completed during the period; and 2,800 units were 24% 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. 23,800 b. 28,200 c. 26,600 d. 31,000