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: Triangle of koch is landmark for AV node with its transition zone. It is bounded by tendon of todaroQ (superiorly), tricuspid valve septal leafletQ (inferiorly) and coronary sinus orificeQ (basally)