Weighted Average Cost (AVCO) under Perpetual Inventory System Steps:

• Start with opening inventory: 20 items × $5 =$100 total cost, average $5 per item.
• Add March 6 purchase: 12 items × $9 =$108, new total cost $100 +$108 = $208, total items 20 + 12 = 32.
• Calculate AVCO: $208 ÷ 32 items =$6.50 per item.
• Closing inventory on March 7 (before March 17 sale): 32 items valued at $6.50 each.

Not enough information: The calculated AVCO per unit is $6.50, which does not match any choice; sales on March 17 occur after closing date, but choices suggest possible error in dates or numbers.

Final answer: Not enough information.