This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thorax, Subject name: Anatomy
Torus aorticus involves: 
Select and explain. 
A. Left atrium, B. Arch of aorta, C. Ascending aorta, D. Right atrium
D: Right atrium
Answer: D: Right atrium 
Explanation: Ans. d (Right atrium). (Ref. Grey, Anatomy, 36th ed., 644)Torus aorticusAnterosuperior part of septal wall of right atrium bulges to some degree into the atrial cavity as torus aorticus. It is caused by proximity of right posterior aortic sinus and cusp.Torus auditoryThe postero-inferior wall of external meatus occasionally presents a smooth to roughened longitudinal elevation, known as auditory torus.Torus mandibularisAbove myelohyoid line, the bone medial to roots of molar teeth is sometimes developed into a rounded ridge called torus mandibularis.Torus palatineIntermaxillary sutures are sometimes raised forming a longitudinal midline ridge.Torus maxillarisIt is occasionally present on the alveolar process spanning the palatal aspect of subcervical roots of upper molar teeth.