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: ENT
Passavant's ridge is formed by - 
Select and explain. 
A. Palatoglossus, B. Superior constrictor, C. Salpingopharyngeus, D. Palatopharyngeus
D: Palatopharyngeus
Answer: D: Palatopharyngeus 
Explanation: It is a mucosal ridge raised by fibres of palatopharyngeus.
It encircles the posterior and lateral walls of the nasopharyngeal isthmus.
Soft palate makes firm contact with this ridge to cut off nasopharynx from oropharynx during deglutition or speech. (Disease of ENT, P.L Dhingra)