Department A had 4,400 units in Work in Process that were 66% completed at the beginning of the period at a cost of $6,400. During the period, 28,600 units of direct materials were added at a cost of $65,780, and 30,600 units were completed. At the end of the period, 2,400 units were 38% completed. All materials are added at the beginning of the process. Direct labor was $28,000 and factory overhead was $4,200. The cost of the 2,400 units in process at the end of the period if the first-in, first-out method is used to cost inventories was Oa, $6,034 Ob. $5,520 Oc. $6.547 Od. $7,574