The correct answer is D. Geneva.
The World Trade Organization (WTO) is an intergovernmental organization that regulates international trade. The organization was established on 1 January 1995 as the successor to the General Agreement on Tariffs and Trade (GATT). The WTO’s headquarters is located in Geneva, Switzerland.
Vienna is the capital of Austria and the seat of the United Nations Office at Vienna. Paris is the capital of France and the seat of the Organisation for Economic Co-operation and Development (OECD). Bern is the capital of Switzerland and the seat of the International Labour Organization (ILO).
The WTO’s headquarters is located in Geneva, Switzerland, because Geneva is a neutral city that is not aligned with any particular country or political bloc. This neutrality is important for the WTO, as it allows the organization to function as a forum for international trade negotiations. Geneva is also a major center for international organizations, which makes it a convenient location for the WTO’s headquarters.