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: Anatomy
[{'content': 'Passavant ridge is seen in? \nSelect and explain. \nA. Oropharynx, B. Nasopharynx, C. Laryngopharynx, D. Lateral nasal wall', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Nasopharyngeal Isthmus: Fibres of palatopharyngeus muscle (arising from palatine aponeurosis) +upper fibres of superior constrictor muscle form incomplete raised ring at posterior & lateral pharyngeal wall known as = Passavant ridge.', 'role': 'assistant'}]