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: Pathology
[{'content': 'The most common benign tumor occurring in oral cavity is: \nSelect and explain. \nA. Papilloma, B. Fibroma, C. Adenoma, D. Epulis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]