Answer:
B. They increase or decrease supply or demand.
Explanation:
In microeconomic theory, prices vary according to the supply and demand of goods and services. When demand is greater than supply, price increases and when supply is greater than demand, price decreases. This is because the economy tends to balance, that is, there is a price that will match supply and demand. At this point, all units produced will be demanded. Price fluctuations change the equilibrium parameters of the economy, however, when this occurs, supply and demand tend to adjust to the new price. For example, if price has decreased, demand tends to increase and supply tends to decrease. Thus a new equilibrium point is established.
