Countries Tend to Specialize in the Production of Goods in Which

Countries tend to specialize in the production of goods in which they have a comparative advantage because

A) government officials calculate opportunity costs and suggest to people what they ought to produce.
B) people want to make a profit.
C) the Economic Development Office of the United Nations hires economic experts to calculate the opportunity costs of different goods in different countries and then suggests to countries what they ought to produce.
D) the United Nations hires economic experts to calculate the opportunity costs of different goods in different countries and then suggests to countries what they ought to produce.