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: Medicine
[{'content': "100% recurrence of disease in Down's syndrome \nSelect and explain. \nA. Translocation of 15 + 21 chromsome, B. Mosaic pattern, C. Trisomy - (21, 21 translocation), D. Non Dysjunction", 'role': 'user'}, {'content': "Answer: C \nExplanation: 100% recurrence of disease in Down's syndrome is due to balanced translocation (21 : 21).", 'role': 'assistant'}]