Department A had 4,900 units in Work in Process that were 61% completed at the beginning of the period at a cost of $6,700. During the period, 31,200 units of direct materials were added at a cost of $71,760, and 33,600 units were completed. At the end of the period, 2,500 units were 36% completed. All materials are added at the beginning of the process. Direct labor was $27,400 and factory overhead was $4,800. The cost of the 2,500 units in process at the end of the period if the first-in, first-out method is used to cost inventories was

a.$6,210

b.$7,590

c.$6,670

d.$5,750