Inventory records for Herb's Chemicals revealed the following: March 1, 2021, inventory: 1,200 gallons @$7.6 per gallon = $9,120 Sales: Purchases: 640 gals $7.65 840 gals $7.70 640 gals@ $7.75 Mar. 5 440 gals Mar. 14 740 gals Mar. 20 540 gals Mar. 26 740 gals Mar. 10 Mar. 16 Mar. 23 The ending inventory under a periodic inventory system assuming average cost (rounding unit cost to three decimal places) is: Multiple Choice $6,591 $6,611 $6,581 $6,509