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
Which of the following represents the additional component in pentalogy of Fallot? 
Select and explain. 
A. Atrial Septal Defect (ASD), B. Ventricular Septal Defect (VSD), C. Right ventricular Hypertrophy (RVH), D. Pulmonic Stenosis
A: Atrial Septal Defect (ASD)
Answer: A: Atrial Septal Defect (ASD) 
Explanation: a. Atrial Septal Defect (ASD)(Ref: Nelson's 20/e p 2211-2217, Ghai 8/e p 420-423)Pentalogy of Fallot = Tetralogy of Fallot + Atrial Septal defect.