This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Hypersensitivity, Subject name: Pathology
Which of the following is secreted by classically activated macrophages (M1)? 
Select and explain. 
A. IL-1, B. IL-2, C. IL-4, D. IL-3
A: IL-1
Answer: A: IL-1 
Explanation: Classically activated macrophages (M1 cells) produce Interleukin (IL)-1 IL-12 IL-23 Chemokines Reactive oxygen species Nitric oxide Lysosomal enzymes