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': 'What is most common type of carcinoma of the right colon - \nSelect and explain. \nA. Stenosing, B. Ulcerative, C. Tubular, D. Fungating', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Ulcerative", 'role': 'assistant'}]