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: Surgery
[{'content': 'A 60 yr old smoker came with the history of painless gross hematuria for one day. The investigation of choice would be : \nSelect and explain. \nA. Urine routine and microscopy, B. Plain x-ray KUB, C. USB KUB, D. Urine for malignant cytology', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]