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. Superior constrictor and palatopharyngeus, B. Inferior constrictor and palatopharyngeus, C. Superior constrictor and palatoglossus, D. Inferior constrictor and palatoglossus", 'role': 'user'}, {'content': 'Answer: A \nExplanation: It is a mucosal ridge raised by fibres of palatopharyngeus. It encircles the posterior and lateral walls of the nasopharyngeal isthmus.\nSoft palate, during its contraction, makes firm contact with this ridge to cut off nasopharynx from the oropharynx during the deglutition or speech.', 'role': 'assistant'}]