This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Renal physiology, Subject name: Physiology
Which is only filtered into renal tubules? 
Select and explain. 
A. DTPA, B. DMSA, C. MAG3, D. EC
A: DTPA
Answer: A: DTPA 
Explanation: Renal DTPA scan is a process for diagnosis and evaluation of kidney functioning. It involves intravenous administration of radiopharmaceutical material to assess the drainage pattern of kidneys and to find out if any area is not functioning properly. This painless, non-invasive technology has revolutionised the world of medicine. Ref: guyton and hall textbook of medical physiology 12 edition page number: 465,466,467