Use the data in the preceding problem to answer the following questions. Now suppose that the United States allows no oil imports.
a. What are the equilibrium price and quantity for oil in the United States?
b. If the United States imposed a price ceiling of $65 per barrel on the oil market and prohibited imports, would there be an excess supply or an excess demand for oil? If so, how much?

c. Under the price ceiling, quantity supplied and quantity demanded differ. Which of the two will determine how much oil is purchased? Briefly explain why.