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
A patient has IDDM diagnosed at age of 15 years. The most reliable indicator for diabetic nephropathy is - 
Select and explain. 
A. 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
B: Urinary protein >550 mg per day for 3 consecutive samples
Answer: B: Urinary protein >550 mg per day for 3 consecutive samples 
Explanation: None