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': 'External cephalic version is contraindicated in all except: \nSelect and explain. \nA. Breech, B. Twins, C. Placenta pre, D. Previous', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Breech', 'role': 'assistant'}]