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: ENT
[{'content': "Premalignant lesion of oral cavity includes -a) Erythroplakiab) Fordyce's spotc) Leukoplakiad) Keratoacanthoma e) Aphthous ulcer \nSelect and explain. \nA. a, B. bc, C. ac, D. b", 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]