Department A had 4,100 units in Work in Process that were 76% completed at the beginning of the period at a cost of $6,000. During the period, 29,600 units of direct materials were added at a cost of $68,080, and 31,100 units were completed. At the end of the period, 2,600 units were 21% completed. All materials are added at the beginning of the process. Direct labor was $27,000 and factory overhead was $4,000. The cost of the 2,600 units in process at the end of the period if the first-in, first-out method is used to cost inventories was

a. $5,980

b. $6,573

c. $7,166

d. $6,277