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: Medicine
[{'content': 'Endoscopy is contraindicated in \nSelect and explain. \nA. Achalasia, B. Peptic stricture, C. Esophageal carcinoma, D. Esophageal web', 'role': 'user'}, {'content': "Answer: A \nExplanation: Endoscopy is C/I in regurgitant lesions like Achalasia and Zenker's diverticulum\xa0as it carries the risk of rupture in mediastinum (Very risky).", 'role': 'assistant'}]