please do it in 15 minutes please urgently.. I'll give you up thumb definitely

The activity for a specific inventory item for the month of March was as follows: # of Per Unit Total Units Cost Cost October 1 inventory 30 $28 $840 Purchases: October 5 100 30 3,000 October 13 60 32 1,920 October 15 90 36 3,240 Goods Available for Sale 280 $9.000 Sales: October 8 110 October 22 120 230 Using weighted average cost under a periodic inventory system, what is the balance of Ending Inventory (round intermediate and final calculations to the nearest dollar) as at October 31? $2,160 $1,980 $1,920 $2,040