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: Medicine
Commonest congenital heart disease is: 
Select and explain. 
A. Mitral valve prolapse, B. Atrial septal defect, C. Ventricular septal defect, D. Persistent ductus arteriosus
C: Ventricular septal defect
Answer: C: Ventricular septal defect 
Explanation: VSD is the most common congenital cardiac defect.