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
Duration of 2nd heart sound is: 
Select and explain. 
A. 0.15 sec, B. 0.12 sec, C. 0.08 sec, D. 0.1 sec
B: 0.12 sec
Answer: B: 0.12 sec 
Explanation: Second heart sound duration is 0.1 to 0.14 sec (average 0.12 sec).