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': 'Premature rupture of membrane is rupture : \nSelect and explain. \nA. At less than 32 weeks, B. Before onset of labour, C. Before 2nd stage of labour, D. All of the above', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Before onset of labour', 'role': 'assistant'}]