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
[{'content': 'Not a bone of quadrilateral cailage: \nSelect and explain. \nA. Ethmoid, B. Vomer, C. Sphenoid, D. Maxilla', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Sphenoid', 'role': 'assistant'}]