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': 'All these drugs are known to exacerbate psoriasis, except: \nSelect and explain. \nA. Lithium, B. Beta blocker, C. Ciclosporin, D. Hydroxychloroquine', 'role': 'user'}, {'content': 'Answer: C \nExplanation: It is a systemic agent used in treatment of psoriasis.', 'role': 'assistant'}]