A Circuit Court of Appeals May Meet "En Banc," Meaning

A circuit court of appeals may meet "en banc," meaning that

A) the entire court must unanimously agree to convene.
B) it is meeting in secret.
C) the court does not publish its rulings.
D) the litigant appeals from the three-judge panel (chosen from a pool of ten or more) to the full circuit court.
E) the case is heard without the justices having actually to be present but the ruling by the attorneys may be appealed to the full court.