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
Boundary of the Kochs triangle is not formed by- 
Select and explain. 
A. Tricuspid valve ring, B. Coronary sinus, C. Tendon of todaro, D. Limbus fossa ovalis
D: Limbus fossa ovalis
Answer: D: Limbus fossa ovalis 
Explanation: Boundaries of triangle of Koch
-        Superior- Tendon of Todaro
-        Inferior- Septal leaflet of Tricuspid valve
-        Basal- Coronary sinus orifice