Department E had 4,000 units in Work in Process that were 40% completed at the beginning of the period at a cost of $12,500. During the period, 14,000 units of direct materials were added at a cost of $28,700 and 15,000 units were completed. At the end of the period, 3,000 units were 75% completed. All materials are added at the beginning of the process. Direct labor was $32,450, and factory overhead was $18,710. The number of equivalent units of production for the period for conversion if the first-in, first-out method is used to cost inventories was Oa. 14,850 Ob. 14,150 Oc. 14,650 Od. 15,650