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: Surgery
[{'content': 'Maximum dilatation of esophagus occurs in- \nSelect and explain. \nA. Carcinoma at gastro esophageal junction, B. Achalasia cardia, C. Stricture at lower end, D. CREST syndrome', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]