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': "25 yr old male having fever & malaise since 2 weeks, ahritis of ankle joint and tender erytematous nodules over the shin. Diagnosis is: \nSelect and explain. \nA. Erythema nodosum, B. Hansen'sdisease, C. Weber- Christian disease, D. Nodular Vasculitis", 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e. Erythema nodosum', 'role': 'assistant'}]