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
[{'content': "Passavant's ridge is formed by - \nSelect and explain. \nA. Palatoglossus, B. Superior constrictor, C. Salpingopharyngeus, D. Palatopharyngeus", 'role': 'user'}, {'content': 'Answer: D \nExplanation: It is a mucosal ridge raised by fibres of palatopharyngeus.\nIt encircles the posterior and lateral walls of the nasopharyngeal isthmus.\nSoft palate makes firm contact with this ridge to cut off nasopharynx from oropharynx during deglutition or speech. (Disease of ENT, P.L Dhingra)', 'role': 'assistant'}]