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
[{'content': 'Calculate the filtration,if GFR = 125 ml / min and renal plasma = 625 ml / min \nSelect and explain. \nA. 5%, B. 20%, C. 50%, D. 10%', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]