At the beginning of February, Zenna Inc. had 100 inventory units that had been purchased at $1 each. On February 5, Zenna purchased 200 units of inventory for $2.5 each. Then on February 11, Zenna sold 250 units of inventory for a price of $5 each. Zenna uses moving average method for inventory valuations. What is the amount of cost of goods sold for the month of February? Select one: a. $550 b. $475 c. $500 d. $100 e. $437.50