This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Psychiatry
[{'content': 'All of the following are features of dementia, EXCEPT: \nSelect and explain. \nA. Insidious in onset, B. Usually irreversible, C. Clouding of consciousness present, D. Hallucinations are rare', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Dementia is a persistent progressive impairment in intellectual function. It is associated with loss of memory and at least one of the following cognitive domains such as aphasia, apraxia, agnosia and impaired executive function. Clouding of consciousness is not seen in dementia, it is seen in delirium. Ref: Current Medical Diagnosis and Treatment 2012, chapter 4.', 'role': 'assistant'}]