This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Head and neck, Subject name: Surgery
[{'content': 'The most common cyst of the oral region is \nSelect and explain. \nA. Dentigerous cyst, B. Keratosis cyst, C. Dermoid cyst, D. Periapical cyst', 'role': 'user'}, {'content': 'Answer: D \nExplanation: repeated question.', 'role': 'assistant'}]