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
10 year old child has violaceous papule and pterygium of nails. The diagnosis is – 
Select and explain. 
A. Psoriasis, B. Pemphigus, C. Pemphigoid, D. Lichen planus
D: Lichen planus
Answer: D: Lichen planus 
Explanation: None