A free market is an economy system where the prices for services and goods are set freely between the vendors and consumers. There is no interventions by the government, price-setting monopoly or other authority. From the choices given, the best answer would be politics. Politics will not influence a free market.
Probably it would be WOOD AND PLASTER AND STONE , CUZ in the 1600s houses were made like that
The Open Door Policy was started by the United States for the purpose of protecting equal privileges among countries trading with China.
