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: Pathology
[{'content': 'Most common cause of hypehalamic hypogonadotrophic failure in men: AI 10 \nSelect and explain. \nA. Klinefelter syndrome, B. Noonan syndrome, C. Viral orchitis, D. Kallmann syndrome', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. Klinefelter syndrome', 'role': 'assistant'}]