The key feature of a market system is
A. competition.
B. profit.
C. demand.
D. supply.
B? A? What does your book say?
http://www.investopedia.com/terms/m/marketeconomy.asp
The key feature of a market system is A. competition.
To arrive at this answer, you need to understand what a market system is and then identify the key characteristic that distinguishes it from other economic systems.
A market system, also known as a free market or a capitalist system, is an economic system where the price of goods and services is determined by supply and demand, with little or no government intervention. In a market system, individuals and businesses engage in voluntary exchanges, buying and selling items based on their preferences and needs.
Competition is the driving force behind a market system. It is the rivalry between buyers and sellers that results in lower prices, better quality products, and innovation. In a competitive market, multiple businesses offer similar products or services, and consumers have the freedom to choose which business to buy from based on price, quality, and other factors.
Profit, demand, and supply are important elements in a market system, but they are not the key feature that distinguishes it from other economic systems. Profit is the monetary gain made by businesses when their revenues exceed their expenses. Demand refers to the desire and willingness of consumers to buy a particular product or service. Supply refers to the quantity of a product or service that businesses are willing and able to provide to the market.
Therefore, the correct answer is A. competition.