Partridge Bookstore had 500 units on hand at January 1, costing $9 each. Purchases and sales during the month of January were as follows: Date Purchases Sales Jan. 14 375 @ $14 17 250 @ $10 25 250 @ $11 29 260 @ $16 Partridge does not maintain perpetual inventory records. According to a physical count, 365 units were on hand at January 31. The cost of the inventory at January 31, under the FIFO method is: a. $3,285. b. $3,650. c. $3,900. d. $4,015.