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': "Recurrent ulcers occurring on gingiva and palate are\nmost probably: \nSelect and explain. \nA. Aphthous ulcers, B. Herpes simplex, C. Koplick spots, D. Lesions of Behcet's syndrome", 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]