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: Radiology
[{'content': 'Which radionuclide is best suited for measurement of GFR? \nSelect and explain. \nA. DTPA, B. DMSA, C. Ohoiodohippurate, D. EDTA', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. DTPA', 'role': 'assistant'}]