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: Pathology
Which one of the following factors is labelled as cytokine in the pathogenesis of systemic inflammatory response syndrome (SIRS) ? 
Select and explain. 
A. Nitric oxide, B. Complements, C. Leukotrienes, D. Tumor Necrosis factor
D: Tumor Necrosis factor
Answer: D: Tumor Necrosis factor 
Explanation: Ans. is 'd' i.e., Tumor Necrosis factor