Materials costs of $515000 and conversion costs of $178560 were charged to a processing department in the month of September. Materials are added at the beginning of the process; conversion costs are incurred uniformly throughout the process. There were no units in beginning Work in Process, 103000 units were started into production in September, and there were 7600 units in ending Work in Process that were 50% complete @ the end of September. What was the total amount of manufacturing costs assigned to those units that were completed and transferred out of the process in September if the weighted-average method is used?

a) $404,400

b) $648,720

c) $590,560

d) $408,200