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': 'True pelvis refers to : \nSelect and explain. \nA. Upper pa of pelvis, B. Lower pa of pelvis, C. Either of these, D. Neither', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Lower pa of pelvis', 'role': 'assistant'}]