19. Flying Aces manufactures small airplane engines. The company currently makes all te ngine parts in house. have company which will ver, they have an opportunity to purchase carburetors from another enable Flying Aces to manufacture additional engines resulting in a $25,000 increase in net operating income. If Flying Aces continues to manufacture carburetors, the potential $25,000 increase in net operating income is best described as a: A) a product cost B) a variable cost C) an opportunity cost D) a period cost