This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Physiology
[{'content': 'In Plummer-Vinson syndrome, the region involved is \nSelect and explain. \nA. Posterior pharyngeal wall, B. Valleculae, C. Postcricoid region, D. Pyriform sinus', 'role': 'user'}, {'content': "Answer: B \nExplanation: Plummer-Vinson syndrome (PVS), a rare clinical condition, is characterized by a triad of dysphagia, iron deficiency anemia and esophageal web in the post-cricoid region. Ref ganong's review of medical physiology 25e 676", 'role': 'assistant'}]