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
Which of the following tests is most sensitive for detecting early diabetic nephropathy - 
Select and explain. 
A. Serum Creatinine, B. Creatinine clearance, C. Microalbuminuria, D. Ultra sonography
C: Microalbuminuria
Answer: C: Microalbuminuria 
Explanation: None