The Forces of Supply and Demand Assure That

The forces of supply and demand assure that

A) demand curves and supply curves tend to shift to the right as time goes by.
B) the price of a good will eventually rise in response to an excess demand for that good.
C) when the supply curve for a good shifts, the demand curve for that good shifts in response.
D) the equilibrium price of a good will be rising more often than it will be falling.