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': 'DSM-IV criterion for depression is \nSelect and explain. \nA. 1 week, B. 2 week, C. 3 week, D. 4 week', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The duration of symptoms of depression according to DSM-5 diagnostic criteria for major depression is 2 weeks. DSM IV is older version of DSM., present version is 5th.', 'role': 'assistant'}]