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': 'What is the best time to give oral psoralen with UVA? \nSelect and explain. \nA. Half n hour before UVA, B. 1 hour before UVA, C. Half n hour after UVA, D. 1 hour after UVA', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans is'b' i.e. 1 hour before UVA Psoralens (mostly 8- MOP) is given orally 1-3 hours (average 2 hours) before exposure to UVA.", 'role': 'assistant'}]