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': 'Tuberculous Ulcer of Oral cavity is usually \nSelect and explain. \nA. painless, B. painful, C. itching, D. Asymptomatic', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]