Sheridan Bookstore had 510 units on hand at January 1, costing $8 each. Purchases and sales during the month of January were as follows: Sheridan does not maintain perpetual inventory records. According to a physical count, 270 units were on hand at January 31. The cost of the inventory at January 31, under the FIFO method is: $3240. $2160. $2820. $2700