This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urology, Subject name: Anatomy
[{'content': 'In Genitourinary TB, True is - \nSelect and explain. \nA. Sterile pyuria is consistent finding, B. AFB in early morning sample is always positive, C. MC site is pelvis, D. Commonest cause of pyelonephritis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Sterile pyuria is the rule" - But about 15-20% of patients with tuberculosis have a secondary pyogenic infection, obscuring the clue - sterile pyuria. The tubercle bacilli can be identified on AFB staining of 24 hr urine specimen or the first-morning urine sample collected on 3 successive days." AFB staining is positive in about 60% of cases - Smith\' Urology Most common site of genitourinary tuberculosis is - kidney The commonest cause of pyelonephritis is - E. coli Ref : Smith\'s Urology 17/e p195, 219', 'role': 'assistant'}]