The inventory records for Radford Co. reflected the following Beginning inventory @ May 1 100 units @ $4.00 First purchase @ May 7 300 units @ $4.40 Second purchase @ May 17 500 units @ $4.60 Third purchase @ May 23 100 units @ $4.80 Sales @ May 31 900 units @ $7.80 Determine the amount of gross margin assuming the FIFO cost flow method. $2,920 $3,420 $3,000 $4,020