This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Radiology
In a Down's syndrome patient posted for surgery, the necessary preoperative investigation to be done is - 
Select and explain. 
A. CT Brain, B. Echocardiography, C. Ultrasound Abdomen, D. X-ray cervical spine
B: Echocardiography
Answer: B: Echocardiography 
Explanation: Description:Congenital hea disease affects ~40%. In paicular, defects affecting the endocardial cushion are common: * atrioventricular septal defect (AVSD): considered the commonest cardiac defect associated with Down syndrome * ostium primum atrial septal defect (ASD) * ventricular septal defect (VSD)