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 most characteristic finding in lichen planus is – \nSelect and explain. \nA. Civatte bodies, B. Basal cell degeneration, C. Thinning of nail plate, D. Violaceous lesions', 'role': 'user'}, {'content': 'Answer: B \nExplanation: "The basic pathology in lichen planus is the damage to the basal cell layer of epidermis leading to hydropic\xa0degeneration of basal cells".', 'role': 'assistant'}]