This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Types of Genetic Disorders, Subject name: Pediatrics
For karyotyping, the dividing cells are arrested by the addition of colchicine in which of the following mitotic phase? 
Select and explain. 
A. Prophase, B. Metaphase, C. Anaphase, D. Telophase
B: Metaphase
Answer: B: Metaphase 
Explanation: Chromosomes are examined after arresting dividing cells in metaphase with mitotic spindle inhibitors (e.g., N-diacetyl N-methylcolchicine), followed by staining.