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
All these drugs are known to exacerbate psoriasis, except: 
Select and explain. 
A. Lithium, B. Beta blocker, C. Ciclosporin, D. Hydroxychloroquine
C: Ciclosporin
Answer: C: Ciclosporin 
Explanation: It is a systemic agent used in treatment of psoriasis.