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 of the following may occur in Down's syndrome except \nSelect and explain. \nA. Hypothyroidism, B. Undescended testis, C. Ventricular septal defect, D. Brushfield's spots", 'role': 'user'}, {'content': 'Answer: B \nExplanation: congenital or acquired hypothyroidism,brush field spots in iris,and ventricular septal defect IS seen in a case with down syndrome.\nUndescended testis is not a feature.', 'role': 'assistant'}]