This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Head & Neck, Subject name: Anatomy
Choose the appropriate lettered structure in this MRI scan showing a transaxial section through the head. Which structure is formed by the perpendicular plate of the ethmoid bone, vomer, and septal cartilage? 
Select and explain. 
A. A, B. B, C. C, D. D
A: A
Answer: A: A 
Explanation: (a) The nasal septum is formed primarily by the perpendicular plate of the ethmoid bone, vomer, and septal cartilage.