This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: JIPMER 2018, Subject name: Anatomy
[{'content': 'The marked area develops from(in green colour) \nSelect and explain. \nA. Septum Primum, B. Septum secundum, C. Ostium primum, D. Ostium secundum', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The marked area is floor of fossa ovalis that developes from septum primum', 'role': 'assistant'}]