This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pharynx, Subject name: ENT
Which of the following is not included in hypopharynx? 
Select and explain. 
A. Pyriform fossa, B. Post cricoid region, C. Anterior pharyngeal wall, D. Posterior pharyngeal wall
C: Anterior pharyngeal wall
Answer: C: Anterior pharyngeal wall 
Explanation: (c) Anterior pharyngeal wall(Ref. Scott Brown, Vol 3; 743)Anterior pharyngeal wall is no entity. Anterior to the hypopharynx is the larynx. Anterior to the nasopharynx and oropharynx are nasal and oral cavities respectively.