This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Microbiology
[{'content': 'Diagonal conjugate is defined as the distance between \nSelect and explain. \nA. Upper border of symphysis pubis and the sacral promontory, B. Lower border of symphysis pubis and the sacral promontory, C. Lower border of symphysis pubis and the third piece of sacrum, D. Lower border of symphysis pubis and tip of sacrum', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The diagonal conjugate is clinically estimated by measuring the distance from the sacral promontory to the lower margin of the symphysis pubis.', 'role': 'assistant'}]