The correct option is D Epiglottis
Pharynx is a structure which is situated above the larynx or the voice box. Pharynx is a common passage for both food and air. After this common pathway, food enters the oesophagus and goes to the stomach while the air enters the trachea via the larynx and goes to the lungs. Epiglottis is a cartilaginous flap that covers the glottis, which is a part of the larynx. During the swallowing process, epiglottis covers the glottis. This is done to ensure that the food does not accidentally enter the trachea via the larynx. Coughing is done in order to expel the food that may have entered the wind pipe due to the improper movement of the epiglottis.