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': 'Which of the following is wrong statements: \nSelect and explain. \nA. Koilonychia in Vit B12 deficiency, B. Oncholysis in Psoriasis, C. Mees lines in Arsenic poisoning, D. Pterygium of nailis in Lichen Planus', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans: A i.e. Koilonychia in Vit B12 deficiency. Koilonychia (Spoon nail) The nail is concave with raised edges. Seen in Iron Deficiency Anemia,Hypothyroidism,Lichen Planus.', 'role': 'assistant'}]