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
Which of the following structuers is inferior to spheno petrosal Synchondrosis- 
Select and explain. 
A. Abducens nerve, B. Osseous pa of auditory tube, C. Cailaginus pa of auditory tube, D. Petro squamous sinus
C: Cailaginus pa of auditory tube
Answer: C: Cailaginus pa of auditory tube 
Explanation: Sphenopetrosal synchondrosis is cailagenous union b/w lateral half margin of great wing of sphenoid & petrous bone. On the under surface of sphenopetrosal synchondrosis, is a furrow, the sulcus of auditory tube for lodgement of cailagenous pa of auditory tubeQ