This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Surfaces and Grooves, Subject name: Anatomy
[{'content': 'A structure marked with a red arrow is derived from which of the following ? \nSelect and explain. \nA. Bulbous venosus, B. Septum primum, C. Endocardial cushion, D. Left venous valve', 'role': 'user'}, {'content': 'Answer: C \nExplanation: A structure marked with a red arrow is derived from endocardial cushion Structures derived from endocardial cushion are : Atrial septum Membranous pa of ventricular septum Atrioventricular canal, valves Aoo-pulmonary channels Any endocardial cushion defect = Cardiac malformation', 'role': 'assistant'}]