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': 'Neutral substance which have size of 6 nm are \nSelect and explain. \nA. Freely filtered, B. Permeability is inversely proportional to diameter, C. Not filtered, D. None of the above', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Neutral substances\n< 4nm\xa0⇒ freely filtered\n> 8mm\xa0⇒ not filtered\n4nm - 8nm\xa0⇒ Permeability is inversely\xa0proportional to diameter', 'role': 'assistant'}]