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': 'Smallest diameter of true pelvis is: \nSelect and explain. \nA. Interspinous diameter, B. Diagonal conjugate, C. True conjugate, D. Inteuberous diameter', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Interspinous diameter', 'role': 'assistant'}]