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: Skin
[{'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: B i.e. Basal cell degeneration', 'role': 'assistant'}]