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
Classical pathway macrophage activating molecule: 
Select and explain. 
A. IFN-U, B. IL-4, C. IL-13, D. IL-1
A: IFN-U
Answer: A: IFN-U 
Explanation: MECHANISM OF CHRONIC INFLAMMATION