At May 1, 2020, Vaughn Company had beginning inventory consisting of 240 units with a unit cost of $5.40. During May, the company purchased inventory as follows: 740 units at $5.40 620 units at $7.00 The company sold 1050 units during the month for $11 per unit. Vaughn uses the average cost method. The average cost per unit for May is O $6.020. O $6.400. $5.900. O $5.400.