Answer:
B, relative prices change constantly to reflect changes in supply and demand.
Explanation:
Prices of goods and services in any market change regularly or constantly. This usually shows the changes in demand and supply of the goods or service.
When the demand for a good is high, prices change and there is an increase. When the demand for a good is low, prices also change and become low as there are not as much people willing to buy the good.
For supply, when the supply of a good or service is high, the price of the good or service is reduced as there is abundant supply of the good. But when the supply of the good is not as much the prices of the good changes as there is an increase.
I hope this helps.