This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Genetic and genetic disorders, Subject name: Pediatrics
[{'content': 'Klinefelter syndrome is diagnosed by \nSelect and explain. \nA. Karyotyping, B. USG abdomen, C. Triple test, D. Echocardiography', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Persons with Klinefelter syndrome are identified with the help of karyotyping. 80% of children with klinefelter syndrome have a male karyotype of X-47,XXY,while the remaining 20% have multiple sex mosaicism or structurally abnormal X chromosome Reference: (Nelson TB of pediatrics pg 410 edition 19.', 'role': 'assistant'}]