Matthew company manufactures phones in a two-department process that involve assembly and finishing. the assembly department reported the follow data for the past month:

direct materials added $336,000

direct labor 460,320

factory overhead 204,000

total costs to account for $1,000,320

units started 80,000

units completed and transferred 67,200

units not complete 12,800

units in beginning inventory 0

The partially complete units at the end of the month were 100 percent complete with respect to materials and 75 percent complete with respect to conversion costs. The unit cost of conversion costs is _______. show your work

a) $3.00

b) $6.00

c) $8.65

d) $9.00