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
Klinefelter syndrome is: MP 07, 10; Maharashtra 09; Gujarat 10; AFMC 12 
Select and explain. 
A. 45XO, B. 46XY, C. 45XY, D. 47XXY
D: 47XXY
Answer: D: 47XXY 
Explanation: Ans. 47XXY