At May 1,2020 . Sheffield Company had beginning inventory consisting of 220 units with a unit cost of $7.20. During May, the company purchased inventory as follows: 720 units at $7.20 660 units at $8.00 The company soid 1130 units during the month for $12 per unit. Sheffeld uses the average cost method. The average cost per unit for May is $7.700.$8.200$7.200$7.530