This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Genetics And Genetic Disorders, Subject name: Pediatrics
[{'content': 'For karyotyping, the dividing cells are arrested by the addition of colchicines in the following mitotic phase \nSelect and explain. \nA. Prophase, B. Metaphase, C. Anaphase, D. Telophase', 'role': 'user'}, {'content': "Answer: B \nExplanation: b. Metaphase(Ref: Nelson's 20/e p 605-606, Ghai 8/e p 645)Chromosomes are examined after arresting dividing cells in metaphase with mitotic spindle inhibitors (e.g., N-diacetyl- N-methylcolchicine), followed by staining.", 'role': 'assistant'}]