A country has a comparative advantage in the production of a good when it can produce that good at a lower opportunity cost compared to other goods. Given the options provided, the correct response would be:
Country X didn't have to give up a more profitable form of production in order to grow cotton.
This indicates that the opportunity cost of producing cotton is lower for Country X than for other countries, which is the definition of comparative advantage. The other options refer to tariffs, domestic industries, or selling prices, which do not directly relate to the concept of comparative advantage.