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': 'Which among the following is the smallest diameter of true pelvis? \nSelect and explain. \nA. Interspinous diameter, B. Diagonal conjugate, C. True conjugate, D. Inteuberous diameter', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Interspinous or bispinous diameter is the distance between the tip of the two ischial spines. It measures 10.5 cm. Diagonal conjugate is the distance between the lower border of symphysis pubis to the midpoint on the sacral promontory. It measures 12 cm. True conjugate or anatomical conjugate or conjugate vera is the distance between the midpoint of the sacral promontory to the inner margin of the upper border of symphysis pubis. It measures 11 cm. Inteuberous diameter is the distance between the inner borders of ischial tuberosities. It measures 11 cm. Ref: Textbook of Obstetrics by D C Dutta, 6th edition, Page 91.', 'role': 'assistant'}]