What Is an Accessory Organ of the Digestive System

What is an accessory organ of the digestive system?

A) An organ that food passes through, but it does not secrete any digestive enzymes
B) An organ that is not necessary for the digestion process
C) An organ that contributes secretions into the alimentary canal, but food does not pass through it
D) An organ that is part of the alimentary canal
E) An organ that accomplishes mechanical digestion of food