Once an Equilibrium Is Achieved,it Can Persist Indefinitely Because

Multiple Choice

Once an equilibrium is achieved,it can persist indefinitely because

A) shocks that shift the demand curve or the supply curve cannot occur.
B) shocks to the demand curve are always exactly offset by shocks to the supply curve.
C) the government never intervenes in markets at equilibrium.
D) in the absence of supply/demand shocks no one applies pressure to change the price.