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: Radiology
[{'content': "In a Down's syndrome patient posted for surgery, the necessary pre-operative investigation to be done is ? \nSelect and explain. \nA. CT Brain, B. Echocardiography, C. Ultrasound Abdomen, D. X-Ray cervical spine", 'role': 'user'}, {'content': "Answer: B \nExplanation: B i.e. Echocardiography Congenital hea disease (especially endocardial cuchion defects) is frequently found in Down's syndrome children.Echocardiography is therefore considered a necessary pre-operative investigation.", 'role': 'assistant'}]