This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Techniques in molecular biology, Subject name: Biochemistry
Klinefelter syndrome is diagnosed by: 
Select and explain. 
A. USG abdomen, B. Echocardiography, C. Triple test, D. Karyotyping
D: Karyotyping
Answer: D: Karyotyping 
Explanation: Klinefelter's syndrom (XXY) can be detected by karyotyping Karyotyping Study of chromosome Best technique for Monosomy/Trisomy But can be only done during Metaphase Sample used: Blood, Bone marrow, Amniotic fluid, Placental tissue Fixative : Carnoy's fixative (Methanol and Glacial Acetic acid in ratio 3:1) Most common stain: Geimsa/G-banding Limitations Can't be done in any phase of cell cycle Can't detect amplifications, microdeletions and complex translocations Low resolution i.e. subchromosomal alterations can't be detected