XoCo, which begins business in May and uses the perpetual method and moving average costing, shows the following data: 20. Purchases Sales May 4 May 11 May 14 May 19 May 21 1,000 7 400 $11 1,400 $ 8 2,000 $10 1,500 @ $15 The balance in XoCo's inventory account on May 31 is .. a. $22,125 b. $20,833 c. $21,705 d. $23,875