This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Ear, Subject name: ENT
What forms lateral wall of mastoid antrum 
Select and explain. 
A. Squamous temporal, B. Tegmen Antri, C. SCC, D. None
A: Squamous temporal
Answer: A: Squamous temporal 
Explanation: Squamous plate of temporal bone (1.5cm) thick in an adult. It is marked externally on the surface of mastoid by supramental triangle. Reference: Dhingra 6th edition