Which of the following agreements must all members of the World Trade Organization sign?

The General Agreement on Tariffs and Trade (GATT) is an accord that was established to promote international trade by reducing or eliminating trade barriers such as tariffs and quotas. It laid the foundation for the global trading system, which evolved into the World Trade Organization (WTO) in 1995. Membership in the WTO requires countries to adhere to GATT's principles, which focus on non-discrimination and transparency in trade.

As a result, every member of the WTO must commit to the agreements derived from GATT, making it a fundamental element of their participation in the organization. The WTO operates on the premise that its members will abide by the rules and commitments outlined in GATT, thus promoting fair competition and trade among its member nations. Therefore, signing the GATT is a prerequisite for being part of the WTO, making it the correct answer.

The other agreements mentioned either pertain to different aspects of international law or trade. The United Nations Convention on the International Sale of Goods (CISG) addresses international sale transactions specifically, and its adoption is not mandatory for WTO membership. The Maastricht Treaty is related to the European Union and focuses on political and economic integration within Europe, while the Paris Convention deals with intellectual property rights and is not a