This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Mood disorders, Subject name: Psychiatry
[{'content': 'Most common age for depression is \nSelect and explain. \nA. Middle age men, B. Middle age female, C. Young girl, D. Children', 'role': 'user'}, {'content': 'Answer: B \nExplanation: An almost universal observation, independent of country or culture, is the twofold greater prevalence of major depressive disorder in women than in men. The mean age of onset for major depressive disorder is about 40 years, with 50 percent of all patients having an onset between the ages of 20 and 50 years. Reference: Synopsis of Psychiatry, page 349.', 'role': 'assistant'}]