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: Physiology
Fever is due to: 
Select and explain. 
A. Interleukin-1, B. Interleukin-2, C. Interleukin-3, D. Interleukin-4
A: Interleukin-1
Answer: A: Interleukin-1 
Explanation: Interleukin-1