This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S, Subject name: Pediatrics
A child with large perimembranous VSD has congestive hea failure. What may be the cause of improvement of failure in this patient 
Select and explain. 
A. Aoic regurgitation, B. Vascular changes in pulmonary circulation, C. Infective endocarditis, D. Closure of VSD spontaneously
B: Vascular changes in pulmonary circulation
Answer: B: Vascular changes in pulmonary circulation 
Explanation: Patients born With uncomplicated VSD may develop pulmonary stenosis due to hyperophy of right ventricular infundibulum ,develop pulmonary aerial hypeension or rarely develop aoic regurgitation. Development of pulmonary aerial hypeension is dreaded complication since if it is of obstructive type the patient becomes inoperable. Ref Ghai pediatrics eighth edition pg no 417