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': 'Thimble pitting of nails is seen in - \nSelect and explain. \nA. Psoriasis, B. Pemphigus, C. Lichen planus, D. Alopecia areata', 'role': 'user'}, {'content': 'Answer: D \nExplanation: most common feature of psoriatic nail is coarse pitting of nail plate Ref Harrison20th edition pg 1208', 'role': 'assistant'}]