Concept:Multilateral trade refers to trade and trade agreements that involve multiple countries, not just two or a few.
Explanation:Trade between two countries only is called bilateral trade.
Trade within the borders of one country is internal or domestic trade.
Trade among many countries, with each country trading with several others under common rules, is called multilateral trade.
Such agreements reduce tariffs, simplify import and export rules, and create a larger market for member nations.
Because so many nations participate, these agreements are broad in scope and often more powerful than bilateral arrangements.
Therefore, the phrase "multilateral trade is carried out" correctly means trade conducted among many countries.
Answer:C. among many countries