Compare FIFO, LIFO, and average cost methods for inventory valuation and their impact on COGS and ending inventory.

• A. FIFO uses newest costs for COGS and oldest for ending inventory; LIFO uses oldest costs for COGS and newest for ending inventory; Average cost uses specific costs for COGS only.
• B. FIFO uses oldest costs for COGS and newest for ending inventory; LIFO uses newest costs for COGS and oldest for ending inventory; Average cost uses weighted-average cost for both.
• C. FIFO uses newest costs for COGS and oldest for ending inventory; LIFO uses oldest costs for COGS and newest for ending inventory; Average cost uses fixed costs for both.
• D. FIFO uses oldest costs for COGS and newest for ending inventory; LIFO uses newest costs for COGS and oldest for ending inventory; Average cost uses weighted-average cost for both.

Answer: (D)