Concept:International trade is governed by the principle of comparative cost advantage.
Explanation:The theory of international trade explains why countries exchange goods and services with one another.
It is based on the idea that each country should specialise in producing goods it can make at a lower opportunity cost.
This idea was introduced by David Ricardo in the 19th century as the principle of comparative cost.
Therefore, the basis of international trade is comparative cost advantage, not management, double entry, or migration.
Answer:B. Principles of comparative cost.