Answer:
Option (a) is correct.
Explanation:
The law of comparative advantage states that a country is producing and exporting a good in which it has a comparative advantage and importing a good in which it has a comparative disadvantage.
Therefore, this will make the countries more specialized and there is an exchange of goods among the trading nations.
Each country is then specialized in the production of a good in which it has a comparative advantage and hence, the joint output of the trading nations increases.