18. Kosinski Bookstore had 200 units on hand at May 1, costing $10 each. Purchases and sales during the month of May were as follows: Date Sales May 5 100 @ $15 15 20 29 200@ $11 150 @ $12 250 @ $16 Kosinski does not maintain perpetual inventory records. According to a physical count, 200 units were on hand at May 31 The cost of the inventory at May 31, under the FIFO method is: a. $2,285. b. $2,350. c. $2,680. d. $2,920