The gain from international trade is:

a. increased employment in the domestic export sector.

b. more goods than would be attainable through domestic production alone.

c. tariff revenue.

d. increased employment in the domestic import sector.

a. increased employment in the domestic export sector

Explanation:

The primary gain from the international trade is more good than, by the attainment through the domestic production alone.

When the countries trade specialization occurs, the countries in which they have comparative advantage produce the good more efficiently. Hence, the resources of other country can be used for the production of some other goods. So people benefit from trade as they get more variety of goods at a lower price and they are able to consume outside their PPF.