Answer: International Monetary Fund (IMF)
Explanation: Nations engage in trade because they don’t produce all the goods that their inhabitants need, as a result countries often develop trade partners, even though they may have the necessary materials to produce them (comparative advantage reasons).
Country B not being able to pay for goods purchased from country A would look to the International Monetary Fund (IMF) for assistance as they can provide the necessary funds needed for balance of trade until country B can pay back from the returns from its exports.
The IMF’s mandate as a sound international financial system is to provide the needed support for vibrant international trade, facilitating the expansion and balanced growth of international trade, and also providing the opportunity for the orderly correction of countries’ balance of payments problems thereby reducing the risk of payment imbalances.