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': 'The prerequisites for internal rotation of the head are all except: \nSelect and explain. \nA. Well-flexed head, B. Efficient uterine contraction, C. Favourable shape of the pelvis, D. Tone of the abdominal muscles', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]