Which of the following is incorrect?

All courts below the Supreme Court  may refer a case involving European Law to the European Court of Justice for a preliminary ruling.

Supreme Court must refer a case involving European Law to the European Court of Justice for a preliminary ruling.

An English court is not bound to give effect to a preliminary ruling of the European Court of Justice.

A preliminary ruling of the European Court of Justice is sent back to the Court which referred the question and must be given effect by that court.