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: Pathology
Most common factor in development of diabetic nephropathy is - 
Select and explain. 
A. Previous kidney disease, B. Associated hypertension, C. Duration of diabetes, D. Control with treatment
C: Duration of diabetes
Answer: C: Duration of diabetes 
Explanation: None