This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Symptoms and signs in psychiatry and classification, Subject name: Psychiatry
[{'content': 'True about delirium are all except \nSelect and explain. \nA. Preserved attention, B. Disturbed sleep, C. Disorientation, D. Hallucination', 'role': 'user'}, {'content': "Answer: A \nExplanation: Delirium is characterized by an acute decline in both the level of consciousness and cognition with paicular impairment in attention. A life threatening, yet potentially reversible disorder of the central nervous system (CNS), delirium often involves perceptual disturbances, abnormal psychomotor activity, and sleep cycle impairment. Reference: Kaplan & Sadock's Synopsis of Psychiatry: Behavioral Sciences/Clinical Psychiatry, 11th Edition, page 697.", 'role': 'assistant'}]