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: Unknown
[{'content': 'The shortest diameter of the pelvic inlet is - \nSelect and explain. \nA. Obstetric conjugate, B. True conjugate, C. Diagonal conjugate, D. Transverse diameter', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans-A', 'role': 'assistant'}]