The correct option is B Both the assertion and reason are true but the reason is not the correct explanation for the assertion
The digestive tract and respiratory tract have a common part which acts as a passage to both food and air. It is called the pharynx. Both the buccal cavity and the nasal cavity open into the pharynx and are separated by the hard palate followed by the soft palate towards the pharyngeal cavity. The terminal end of the soft palate is known as the uvula which is bent towards the pharyngeal cavity. During the swallowing of food, the uvula lifts up and covers the internal nares, and thereby it prevents the entry of food into the nasal passage. The pharynx further opens into two openings- the gullet and the glottis. Gullet opens into the oesophagus which is the food pipe whereas the glottis opens into the larynx which is a part of the respiratory tract. There is leaf-shaped cartilage present over the glottis which is known as the epiglottis. Epiglottis covers the glottis during the swallowing of food to prevent the entry of food into the respiratory tract and further into the larynx, trachea, and lungs.