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: Gynaecology & Obstetrics
[{'content': 'Labour is termed as precipitate if it occurs under: \nSelect and explain. \nA. 1 hour, B. 2 hours, C. 1/2 hours, D. 4 hours', 'role': 'user'}, {'content': 'Answer: B \nExplanation: 2 hours', 'role': 'assistant'}]