(Multiple choice.....choose the correct answer ....without explanation)

Bluemoon Traders provided the following inventory information for the month of December 2018 Units Cost (RO) Amount (RO) 340 22 7,480 220 26 5,720 December - 1 Beginning inventory December 7- Purchases December 15- Purchases December 12 - Sales 380 30 11,400 410 40 16,400 Based on the above table find out the amount of Cost of goods sold for the month of December 2018, if the business is evaluating the inventory by using Weighted average method under the Periodic inventory system. O a. RO 16,400 O b. RO 10,730 O c. RO 13,870 d. RO 11,400