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: Medicine
Which of the following is the most common cause of hypergonadotrophic hypogonadism in males- 
Select and explain. 
A. Viral orchitis, B. Klinefelter's syndrome, C. Kallman's syndrome, D. Noonan syndrome
B: Klinefelter's syndrome
Answer: B: Klinefelter's syndrome 
Explanation: None