Sheffield Bookstore had 450 units on hand at January 1, costing $9 each. Purchases and sales during the month of January were as follows: Date Purchases Sales Jan. 14 385 @ $13 17 260 @ $8 25 260 @ $12 29 230 @ $16 Sheffield does not maintain perpetual inventory records. According to a physical count, 355 units were on hand at January 31. The cost of the inventory at January 31, under the FIFO method is: $2840. O $3880. O $4260. O $3195