The correct answer is C) United States, United Kingdom, Singapore, Hong Kong.
The following lists are nations with mixed economies. The list in which the free market is most dominant is "United States, United Kingdom, Singapore, Hong Kong."
Free market economies support the free trade of goods and services in order to benefit the economies of the participant countries. Free market economies do not have any restrictions form the government and it only intervenes in extreme situations to solve any issues. For international controversies, the World Trade Organization (WTO) intervenes to try to help fix any difference between countries.