Final answer:
The paralysis of cranial nerve VII can cause unilateral facial and gag reflex paralysis.
Step-by-step explanation:
The correct answer is a) VII. The paralysis of cranial nerve VII, also known as the facial nerve, can cause unilateral facial and gag reflex paralysis. The facial nerve controls the muscles of facial expression and is responsible for transmitting taste sensations from the anterior two-thirds of the tongue.
In addition to controlling facial movements and taste sensations, the facial nerve also contains preganglionic parasympathetic fibres that control tear production, salivary glands, and other autonomic functions.
Other cranial nerves have different functions. Cranial nerve VI, also known as the abducens nerve, controls the movement of the lateral rectus muscle of the eye. Cranial nerve X, also known as the vagus nerve, has autonomic functions in the thoracic and superior abdominal cavities. Cranial nerve V, also known as the trigeminal nerve, carries general somatic senses from the head.