This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nose and PNS, Subject name: ENT
The most common site of leak in CSF rhinorrhoea is: 
Select and explain. 
A. Sphenoid sinus, B. Frontal sinus, C. Cribriform plate, D. Tegmen tympani
C: Cribriform plate
Answer: C: Cribriform plate 
Explanation: CSF rhinorrhoea is most commonly iatrogenic, following endoscopic sinus surgery. It can occur in surgery of frontal, sphenoid or ethmoid sinus. Injury to cribriform plate and ethmoid roof is the most common cause.