I would like to know how they got this answer, thanks!

8. Widget Company began the year with 10 units of inventory at a cost of $4 per unit. The company made the following purchases during the year: January 24: 5 units at a per/unit cost of $5 May 13: 12 units at a per/unit cost of $6 September 23: 3 units at a per/unit cost of $7 December 11: 7 units at a per/unit cost of $8 The company sold 15 units on September 1 and uses Periodic LIFO. What was the company's ending inventory balance and COGS for the year, respectively? A. \$107; \$107. B. $127;$87. C. $67;$107. D. None of the above