The pharynx functions as a ______, whereas the larynx functions as a ______.
A. common passage for air and food; passageway for food only
B. passageway for air only; passageway for air and food
C. common passageway for air and food; passageway for air only
D. site to prevent objects from entering the trachea; site to prevent objects from entering the larynx
E. block to bacteria; conduit for air and food