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 extraction is done in all except : \nSelect and explain. \nA. Deep transverse arrest, B. Atter-coming head of breech, C. Delay in first stage due to uterine ineia, D. Delay in descent of high head in case of second baby of twins', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Atter-coming head of breech', 'role': 'assistant'}]