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: Pediatrics
[{'content': "All are common in Down syndrome, except – \nSelect and explain. \nA. Simian crease, B. Clinodactyly, C. Mother's age > 35 years, D. Respiratory tract infection uncommon", 'role': 'user'}, {'content': "Answer: D \nExplanation: Chronic rhinits, conjunctivitis and periodontal disease are common in Down's syndrome.\nLower respiratory tract infections pose a threat to life.\nPneumonias are common in patients with Town's syndrome.", 'role': 'assistant'}]