In the Real World We Don't Observe Countries Completely Specialising

Multiple Choice

In the real world we don't observe countries completely specialising in the production of goods for which they have a comparative advantage.One reasons for this is

A) comparative advantage works better in theory than in practice.
B) some countries have more resources than other countries.
C) tastes for many traded goods are similar in many countries because of globalisation.
D) production of most goods involves increasing opportunity costs.