The Fanzy Supplies began December 2021 with 300 units of inventory at a cost of per unit.$90 During December the business made the following purchases: December 4: 430 units at $91 December 15: 190 units at $92 December 20: 420 units at $93 December 28: 426 units at $ 92 The store uses the periodic inventory system and the physical count at December 31, 2021 indicates that 400 units of inventory are on hand. REQUIRED: 1. Calculate the cost of goods available for sale during December 2. Determine the cost of ending inventory under the FIFO method 3. Calculate the cost of goods sold during the month, 1. Assume sales price is $ 200 per unit, compute the gross margin for December