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': "Chromosome involved in Down's Syndrome is - \nSelect and explain. \nA. 21, B. 22, C. 13, D. X chromosome", 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., 21 o Has been explained in previous sessions", 'role': 'assistant'}]