This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General obstetrics, Subject name: Anatomy
[{'content': 'The 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: True conjugate - 11cm Diagonal conjugate -12 cm Inteuberus diameter -11cm Interspinous diameter -10 cm Ref: Williams Obs 24e pg 32-33.', 'role': 'assistant'}]