单选题 The Mountain Bike Supply Company had 500 units in its beginning inventory. Each of these units cost $ 5. During the period, Mountain Bike Supply first purchased 400 units at $ 6 each and then 200 units at $ 7 each. At the end of the period, Mountain Bike Supply had 600 units. What is the cost of goods sold and inventory for Mountain Bike Supply if it uses FIFO inventory valuation ? COGS Inventory ①A. $ 2500 $ 3100 ②B. $ 3200 $ 3800 ③C. $ 2500 $ 3800