This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anatomy of skin, Subject name: Dental
[{'content': 'Basal cell degeneration seen in - \nSelect and explain. \nA. Lichen Planus, B. Psoriasis, C. pemphigus, D. Pemphigoid', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Lichen planus is an inflammatory T cell mediated autoimmune disorder affecting skin, hair, nails and mucous membranes. Lichen planus triggers T cell mediated autoimmune damage to basal keratinocytes that manifest as altered self antigens on their surface. Ref Harrison20th edition pg 1256', 'role': 'assistant'}]