The correct answer is: B. market where the price of a commodity is determined by free play of the forces of supply and demand.
A free market is a market in which the prices for goods and services are set by the open market and are not subject to government control. In a free market, buyers and sellers are free to transact at any price they agree upon. The price of a good or service is determined by the forces of supply and demand. Supply is the amount of a good or service that producers are willing and able to sell at a given price. Demand is the amount of a good or service that consumers are willing and able to buy at a given price. When supply and demand are equal, the market is said to be in equilibrium. The equilibrium price is the price at which the quantity supplied equals the quantity demanded.
Option A is incorrect because it describes a free trade zone. A free trade zone is a geographic area where goods can be imported and exported without paying customs duties.
Option C is incorrect because it describes a free port. A free port is a port that is exempted from payment of customs duty on articles of commerce, primarily to encourage tourism.
Option D is incorrect because it is not a definition of a free market.