Inventory records for Herb's Chemicals revealed the following: March 1, 2021, inventory: 1,200 gallons @ $7.6 per gallon = $9,120 Purchases: Mar. 10 640 gals @ $7.65 Mar. 16 840 gals @ $7.70 Mar. 23 640 gals @ $7.75 Sales: Mar. 5 440 gals Mar. 14 740 gals Mar. 20 540 gals Mar. 26 740 gals The ending inventory under a periodic inventory system assuming average cost (rounding unit cost to three decimal places) is: Multiple Choice 0 $6,591. 0 $6,611. 0 $6,581. 0 $6,509