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
Which of the following features on X-ray chest can differential an Atrial septal Defect (ASD) from a Ventricular Septal Defect (VSD)? 
Select and explain. 
A. Enlarged Left Atrium, B. Pulmonary Plethora, C. Enlarged pulmonary Aery, D. Enlarged Aoa
A: Enlarged Left Atrium
Answer: A: Enlarged Left Atrium 
Explanation: Left atrial enlargement is not seen in an ASD. In ASD cardiomegaly is due to enlargement of the right atrium and right ventricle. In VSD cardiac silhouette is of left ventricular type. Ref: Essential pediatrics by O.P.Ghai 6th edn/page 401, 403.