Department R had 4,000 units in work in process that were 63% completed as to labor and overhead at the beginning of the period. During the period, 31,300 units of direct materials were added, 32,400 units were completed, and 2,900 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 conversion costs for the period was Oa. 34,779 Ob. 32,400 Oc. 30,779 Od. 39,300