The following data pertaining to a recent period's operations are available :
Beginning Finished Goods Inventory: $12,000
Cost of Goods Manufactured : $36,000
Ending Finished Goods Inventory : $6,000
Gross Margin : 40% of sales
Administrative and selling expenses : $10,000
Question : Net operating income was ?
A) 10,000 B) 18,000 C) 70,000 D) 46,000 E