Bayside Bookstore had 500 units on hand at January 1, costing S10 each. Purchases and sales during the month of January were as follows: Date Purchases Sales Jan. 14 380 @ $15 15 250 @ SII 27 250 @ $12 29 260 @ 517 Bayside does not maintain perpetual inventory records. According to a physical count, 360 units were on hand at January 31 The cost of the inventory at January 31, under the FIFO method is: a. $3,640 b.$3,820 O CS4,210 O d. 84.120