RJ Corporation has provided the following information about one of its inventory items:

Date Transaction Number of Units Cost per Unit

1/1 Beginning Inventory 400 $3,200 6/6 Purchase 800 $3,600

9/10 Purchase 1,200 $4,000

11/15 Purchase 800 $4,200

During the year, RJ sold 3,000 units. What was ending inventory using the average cost flow assumption under a periodic inventory system?

a. $840,000
b. $770,000
c. $640,000
d. $880,000