If an Appellate Court Rules in Favor of the Defense

If an appellate court rules in favor of the defense and decides to overturn the conviction, what happens next?

A) The defendant is acquitted and set free.
B) The case is sent back to the trial court and the defendant may be retried.
C) The prosecution is held in contempt of court.
D) The case is sent to the state supreme court or the U.S. Supreme Court.