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': 'Most common benign esophageal tumour is: \nSelect and explain. \nA. Leiomyoma, B. Rhabdomyoma, C. Adenoma, D. none of the above', 'role': 'user'}, {'content': "Answer: A \nExplanation: Leiomyomas constitute more than 50% of benign esophageal tumors. Ref: Schwaz's principle of surgery 9th edition, chapter 25.", 'role': 'assistant'}]