7. Canyon City Retail uses the moving average flow assumption. On July 1, there were 150 units on hand and the total inventory cost was $750. On July 10, 40 more units were purchased at a cost of $6 apiece. Thirty units were sold on July 3 and 60 units were sold on July 17. What was the total cost of the units sold on July 17? a. $728) b. $330 c. $315 d. $312)