128. David Katz' assembly department has materials cost at $3 per unit and conversion cost at $6 per unit. There are 9,000 units in ending Work in Process, all of which are 70% complete as to conversion costs and fully complete as to direct materials. How much are total costs to be assigned to inventory if the weighted-average method is used?

a) $37,800

b) $64,800

c) $56,700

d) $81,000