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': 'A ranula is a \nSelect and explain. \nA. Type of epulis, B. Sublingual thyroid, C. Thyroglossal cyst, D. Cystic swelling in the floor of the mouth', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]