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 formed by: \nSelect and explain. \nA. Tensor veli palati and superior constrictor, B. Palatopharyngeus and superior constrictor, C. Palatopharyngeus and inferior constrictor, D. Palatoglossus and superior constrictor', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Some fibres of the palatopharyngeus muscle (arising from palatine aponeurosis) sweep horizontally backwards and join the upper\xa0fibres of the superior constrictor muscle to form a U-shaped muscle-loop in the posterior pharyngeal wall underneath the mucosa,\xa0which is pulled forward during swallowing to form the Passavant ridge.', 'role': 'assistant'}]