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': 'Ventouse in 2nd  stage of labour is contraindicated in: \nSelect and explain. \nA. Persistent occipito-posterior position, B. Heart disease, C. Uterine inertia, D. Preterm labour', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]