This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Fetal Skull and Maternal Pelvis, Subject name: Gynaecology & Obstetrics
[{'content': 'Shortest diameter of pelvis is- \nSelect and explain. \nA. Bispinous, B. Antero-posterior, C. Oblique, D. Transverse', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Bispinous", 'role': 'assistant'}]