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: Dental
The pharyngeal structure established in early age and remain constant throughout life is? 
Select and explain. 
A. Depth of oropharynx, B. Depth of nasopharynx, C. Width of nasopharynx, D. Width of oropharynx
B: Depth of nasopharynx
Answer: B: Depth of nasopharynx 
Explanation: Multiple recent researches have concluded that the depth of nasopharynx is established during the first 2 years of life and these dimensions remains constant thereafter.
Ref: Graber LW, Vanarsdall RL, Vig KW, Huang GJ. Orthodontics: current principles and techniques.