In a Market System, What Must Take Place for Quantity

Multiple Choice

In a market system, what must take place for quantity demanded to continually be equated with quantity supplied?

A) Price controls must be applied by governments.
B) Relative prices must be able to adjust to market clearing levels.
C) Tastes and preferences of consumers must adjust to eliminate surpluses or shortages.
D) Businesses must engage in involuntary, unprofitable exchanges to eliminate surpluses or shortages.