Answer: d. Prices
Explanation:
A market system is one in which the forces of demand and supply play a dominant role. In this system forces of demand and supply interact to make decisions on what to produce, how to produce and how much to produce. These forces help us in determining the price of the good, which in turn tell us about the relative scarcity of the good. Thus, in a market system prices provides individuals the information needed to make decisions.
