Correct Answer: Organization of Petroleum Exporting Countries (OPEC)

Solution : The correct answer is (d) Organization of Petroleum Exporting Countries (OPEC).

The Organization of Petroleum Exporting Countries (OPEC) is an intergovernmental organization that consists of oil-producing countries and primarily focuses on coordinating and regulating oil production and prices. While OPEC plays a significant role in the global economy, it is not considered an international economic organization in the same sense as the World Trade Organization (WTO), International Monetary Fund (IMF), and World Bank.