This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Basic Concepts, Subject name: Pathology
[{'content': 'Classical pathway macrophage activating molecule: \nSelect and explain. \nA. IFN-U, B. IL-4, C. IL-13, D. IL-1', 'role': 'user'}, {'content': 'Answer: A \nExplanation: MECHANISM OF CHRONIC INFLAMMATION', 'role': 'assistant'}]