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': 'The commonest pre-malignant condition of oral cancer is \nSelect and explain. \nA. Leukoplakia, B. Aphthous ulcer, C. Lichen planus, D. Erythro-leukoplakia', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Leukoplakia is the most common (~ 85%) of the premalignant lesions of the oral cavity.', 'role': 'assistant'}]