Taste in the 1/3 posterior of your tongue is given by:

A. The trigeminal nerve (CN V) is primarily responsible for sensory information from the face and motor control of the muscles of mastication (chewing). It does not carry taste sensations. Instead, it is involved in sensation (e.g., touch, pain, temperature) of the face and mouth, but not taste.
B. The vagus nerve (CN X) has various functions, including parasympathetic control of the heart, lungs, and digestive tract, and sensory and motor functions in the throat and voice box. It does contribute to taste sensation in the region of the pharynx and the epiglottis, but it is not primarily responsible for the taste sensation on the posterior third of the tongue.
C. The glossopharyngeal nerve (CN IX) is responsible for taste sensation on the posterior one-third of the tongue. It also contributes to the sensory innervation of the pharynx and helps in the regulation of saliva production. This nerve is specifically involved in the taste perception in the back third of the tongue.
D. The facial nerve (CN VII) provides taste sensation to the anterior two-thirds of the tongue. It also controls the muscles of facial expression and contributes to the production of saliva and tears. The facial nerve does not provide taste sensation to the posterior third of the tongue.

A. A hallucination is a sensory experience that occurs without any external stimulus. It involves perceiving things that are not present in the environment, such as hearing voices or seeing things that are not there. The young man hearing his deceased sister talking to him in his head is an example of an auditory hallucination, which is a common symptom in schizophrenia.
B. Perseveration is the repetitive and persistent repetition of a particular response, such as a word or action, despite the absence of a stimulus or the problem being resolved. It is not related to abnormal sensory perceptions but rather to repetitive behaviors or speech. The young man's experience of hearing voices does not fit this description.
C. A fugue state is a type of dissociative disorder where a person suddenly and unexpectedly travels away from home or customary work locations and cannot recall their past. It often involves amnesia for personal history. The scenario described does not involve such travel or amnesia but rather auditory experiences, making this term irrelevant.
D. An illusion is a misperception of an actual external stimulus. It involves incorrectly interpreting a real sensory input, such as mistaking a shadow for a person. Since the young man is not misinterpreting a real external stimulus but rather hearing something that is not present at all, an illusion does not accurately describe his experience.