This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Genetics, Subject name: Pathology
Karyotyping most commonly done under light microscopy: 
Select and explain. 
A. G banding, B. Q banding, C. C banding, D. R banding
A: G banding
Answer: A: G banding 
Explanation: Karyotype Obtained by arranging each pair of autosomes according to length, followed by sex chromosomes. Staining methods have been developed that allow identification of individual chromosomes on the basis of distinctive and reliable pattern of alternating light and dark bands. One most commonly used involves a Giemsa stain and is hence called G banding.