Final answer:
The General Agreement on Tariffs and Trade (GATT) under the World Trade Organization (WTO) is the agreement that allows firms to challenge trade restrictions in Indonesia. The WTO is a global organization that helps in resolving trade disputes and promotes free trade, and GATT has been designed for this purpose among its member nations.
Step-by-step explanation:
The agreement that makes it possible for firms to challenge restrictions in Indonesia that prohibit foreign firms from opening their own wholesale or retail distribution is C. General Agreement on Tariffs and Trade (GATT) under the World Trade Organization (WTO). As a global international organization dealing with the rules of trade between nations, the WTO aims to ensure that trade flows as smoothly, predictably, and freely as possible. The WTO and its agreements like GATT have been signed and ratified by a majority of the world's nations, and are designed to assist in resolving trade disputes and promoting global free trade.
While NAFTA, TPP, and CETA are also significant trade agreements, they do not specifically target or handle trade disputes for Indonesia; NAFTA is focused on North America, TPP originally aimed to enhance trade in the Pacific Rim (including challenges to national regulations, as mentioned in associated information), and CETA is an agreement between the European Union and Canada. It's the GATT agreement administered by the WTO that globally addresses such trade issues, including the ability to challenge discriminatory practices by member nations.