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: Pediatrics
[{'content': 'Major criteria for rheumatic fever - AJE \nSelect and explain. \nA. Carditis, B. Ahralgia, C. Erythema marginatum, D. Subcutaneous nodule', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Ahralgia", 'role': 'assistant'}]