This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: CVS Embryology, Subject name: Anatomy
[{'content': 'The most common cardiac congenital malformations seen clinically is \nSelect and explain. \nA. Persistent truncus aeriosus, B. Membranous VSD, C. Common ventricle, D. Foramen secundum defect', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The most common of all cardiac congenital malformations seen clinically are membranous VSDs. The membranous interventricular septum forms by the proliferation and fusion of tissue from three different sources: Right bulbar ridge Left bulbar ridges Atrioventricular (AV) cushions. Because of this complex formation, the probability of defects is very high.', 'role': 'assistant'}]