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': 'Triangle of Koch is the landmark for : \nSelect and explain. \nA. SA node, B. Bundle of His, C. AV node, D. Purkinje fibres', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Triangle of KochTriangular area in right atrium- Marks the site of AV NODEBoundaries- Anterior : Base of septal leaflet of tricuspid valve- Posterior : Anteromedial margin of opening of coronary sinus- Superiorly : Tendon of Todaro', 'role': 'assistant'}]