Last month, a welding department started 8,000 units into production. The department had 2,000 units in process at the beginning of the month that were 60% complete with respect to conversion costs, and 3,000 units in process at the end of the month that were 30% with respect to conversion costs. A total of 7,000 units were completed and transferred to the next department during the month. Using the weighted average method, the equivalent units of production for conversion costs for the month would be?:

A. 7,900

B. 8,500

C. 9,200

D. 9,300