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': 'Fluctuating level of consciousness is seen in \nSelect and explain. \nA. Hysteria, B. Delirium, C. Dementia, D. Mania', 'role': 'user'}, {'content': "Answer: B \nExplanation: Delirium is characterized by an acute decline in both the level of consciousness and cognition with paicular impairment in attention. Reference: Kaplan & Sadock's Synopsis of Psychiatry: Behavioral Sciences/Clinical Psychiatry, 11th Edition, page 697.", 'role': 'assistant'}]