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
Which of the following procedures is used as a routine technique in karyotyping using light microscopy? 
Select and explain. 
A. G banding, B. C banding, C. Q banding, D. Brd V-staining
A: G banding
Answer: A: G banding 
Explanation: None