Inventory Valuation Methods  
a. Explain the FIFO (First-In, First-Out), LIFO (Last-In, First-Out), and weighted average inventory valuation methods. Discuss the impact of each method on inventory valuation and cost of goods sold during periods of inflation and deflation.
b. ABC Retail Store purchases inventory as follows:
•January 1: 100 units at $10 per unit
•February 1: 150 units at $12 per unit
•March 1: 200 units at $15 per unit
During the month of March, the store sells 300 units. Calculate the cost of goods sold and ending inventory using the FIFO, LIFO, and weighted average methods. Analyze the differences in reported profit and inventory valuation under each method.