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: Physiology
The glomerular filtration rate of the human kidney may be determined by measuring the plasma clearance of: 
Select and explain. 
A. PAH, B. Urea, C. Inulin, D. Glucose
C: Inulin
Answer: C: Inulin 
Explanation: None