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: Medicine
[{'content': 'A patient has IDDM diagnosed at age of 15 years. The most reliable indicator for diabetic nephropathy is - \nSelect and explain. \nA. Urine albumin <50 mg per day in 3 consecutive samples, B. Urinary protein >550 mg per day for 3 consecutive samples, C. Development of diabetic retinopathy, D. Hematuria', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]