This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Kidney & Ureturs, Subject name: Surgery
[{'content': 'A 60 years old male presents with hematuria at onset of micturition, cause is: \nSelect and explain. \nA. Urethral stone, B. Bladder tumor, C. Ureteric stone, D. Prostatitis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (a) Urethral stone* Blood at beginning of urination: Urethral problem* Blood at end of urination: Bladder problem* Blood mixed throughout the process: Prerenal, Renal or vesical', 'role': 'assistant'}]