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
[{'content': 'What forms lateral wall of mastoid antrum \nSelect and explain. \nA. Squamous temporal, B. Tegmen Antri, C. SCC, D. None', 'role': 'user'}, {'content': 'Answer: A \nExplanation: 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', 'role': 'assistant'}]