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
Which of the following is unpaired bone of facial skeleton: 
Select and explain. 
A. Nasal, B. Lacrimal, C. Inferior nasal concha, D. Vomer
D: Vomer
Answer: D: Vomer 
Explanation: Mandible and vomer are the two unpaired bones of facial skeleton.