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
Systolic murmur in TOF is due to? 
Select and explain. 
A. VSD, B. Pulmonary stenosis, C. ASD, D. None
B: Pulmonary stenosis
Answer: B: Pulmonary stenosis 
Explanation: b. Pulmonary stenosis(Ref: Nelson's 20/e p 2223-2225, Ghai 8/e p 424-426)Ejection systolic murmur in TOF is due to pulmonary stenosis.The intensity and duration of this systolic murmur is inversely proportional to the severity of TOF.