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: Dental
[{'content': 'The thinnest epithelium of oral cavity is found in the: \nSelect and explain. \nA. Buccal gingiva, B. Lingual gingiva, C. Oral surface of lip, D. Sublingual mucosa (floor of mouth)', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]