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
X-ray features of ASD are all except – 
Select and explain. 
A. Right atrial enlargement, B. Left atrial enlargement, C. Pulmonary plethora, D. Small aortic knockle
B: Left atrial enlargement
Answer: B: Left atrial enlargement 
Explanation: Radiological features of ASD:- Normal size heart or mild cardiomegaly, normal or enlarged pulmonary artery, pulmonary plethora, enlarged right atrium and ventricle, normal size left atrium, small aortic knob.