Shortages and Surpluses Can Occur in Markets Other Than Those

Multiple Choice

Shortages and surpluses can occur in markets other than those in which government imposes the price floors and ceilings.This phenomenon could be explained by the action of seller(s) :

A) because they set the prices in advance of sales and these prices happen to be below the equilibrium prices.
B) because they set the prices in advance of sales and these prices happen to be above the equilibrium prices.
C) because they do not set the prices in advance.
D) because they set the prices in advance of sales and these prices happen to be below or above equilibrium prices.