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: ENT
Anterior wall of tympanic cavity contains: 
Select and explain. 
A. Promontry, B. Bony pa of pharyngotympanic tube, C. Processus cochleariformis, D. Tensor tympani muscle
D: Tensor tympani muscle
Answer: D: Tensor tympani muscle 
Explanation: The anterior wall has a thin plate of bone which separates the cavity from internal carotid. It also has two openings - the lower one for Eustachian tube and the upper one for the canal of tensor tympani muscle.