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': 'Which of the following is the best known metabolic function of the lung \nSelect and explain. \nA. Inactivation of serotonin, B. Conversion of angiotensin I to angiotensin II, C. Inactivation of bradykinin, D. Metabolism of basic drugs by cytochrome P450 system', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]