This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thorax: Aerial supply, Subject name: Anatomy
[{'content': 'Torus aoicus is seen due to: \nSelect and explain. \nA. Atrium bulging into the aoa, B. Aoic sinus bulging into left atrium, C. Aoic sinus bulging into right atrium, D. Aoic wall tear', 'role': 'user'}, {'content': "Answer: C \nExplanation: Torus aoicus (aoic mound) is the prominent region of the right atrial septum, which marks the projection of the noncoronary aoic sinus into the right atrial wall. The bulge is superior to the coronary sinus and anterior to the fossa ovalis. The right coronary aery arises from the anterior ('right coronary') aoic sinus; The left coronary aery arises from the left posterior (left coronary) aoic sinus.", 'role': 'assistant'}]