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': "Poor prognostic factor in schizopaEUR' hrenia is: \nSelect and explain. \nA. Acute onset, B. Family history of affective disorder, C. Middle age, D. Gradual onset", 'role': 'user'}, {'content': 'Answer: D \nExplanation: Gradual onset', 'role': 'assistant'}]