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
Which of the following is the best-known metabolic function of the lung: 
Select and explain. 
A. Inactivation of serotonin, B. Conversion of angiotensin-I to angiotensin-II, C. Inactivation of bradykinin, D. Metabolism of basic drugs by cytochrome P450 system
B: Conversion of angiotensin-I to angiotensin-II
Answer: B: Conversion of angiotensin-I to angiotensin-II 
Explanation: B i.e. Conversion of angiotensin - Ito angiotension II.