This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Joints, Subject name: Anatomy
[{'content': 'All of the following bones are pneumatic except: \nSelect and explain. \nA. Maxilla, B. Frontal, C. Mandible, D. Ethmoid', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. C. MandiblePneumatic bones are those bones which contain an air filled cavity within them. In humans, they are seen in relation to the nasal cavity - they enclose the paranasal sinuses. Pneumatic bones are - maxilla, frontal bone, sphenoid and ethmoid.', 'role': 'assistant'}]