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
Thimble pitting of nails is seen in 
Select and explain. 
A. Psoriasis, B. Pemphigus, C. Lichen planus, D. Alopecia areata
A: Psoriasis
Answer: A: Psoriasis 
Explanation: Ans. is 'a' i.e., Psoriasis