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
Wrong statement is – 
Select and explain. 
A. Mees line in arsenic poisoning, B. Pterygium of nails in Lichen planus, C. Onycholysis in Psoriasis, D. Koilonychia in Megaloblastic Anemia (B12 def)
D: Koilonychia in Megaloblastic Anemia (B12 def)
Answer: D: Koilonychia in Megaloblastic Anemia (B12 def) 
Explanation: Koilonychia is seen in iron deficiency anemia (not in megaloblastic anemia).
Mees line is seen in Arsenic poisoning.
Pterygium is diagnostic for lichen planus.
Psoriasis can cause onycholysis