A department transferred 7,000 units to the finished goods storeroom during a month. There was no beginning work in process inventory, but 500 units were still in process at the end of the month. Equivalent production for the month was 7,400 units, and production costs incurred totaled $16,800. Inventory costs would be determined using a unit cost of:
a) $2.27
b) $2.40
c) $2.24
d) $2.58