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: Anatomy
[{'content': 'Where is torus aoicus located \nSelect and explain. \nA. Left atrium, B. Right atrium, C. Aoa, D. Left ventricle', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Torus aoicus is a buldge in the right atrial septum sited superiorly and anteriorly. It is produced due to adjacent nonocoronary aoic sinus at the base of ascending aoa. It is superior to coronary sinus and anterior to fossa ovalis.', 'role': 'assistant'}]