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': 'ARM is contraindicated in : \nSelect and explain. \nA. Placenta pre, B. Hydramnios, C. Accidental hemorrhage, D. Twins', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Hydramnios', 'role': 'assistant'}]