This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology, Subject name: Microbiology
[{'content': 'Cachectin is produced by - \nSelect and explain. \nA. Neutrophils, B. Eosinophils, C. Macrophages, D. Basophils', 'role': 'user'}, {'content': 'Answer: C \nExplanation: a protein that is released by activated macrophages as an immune system defense and, when the defense is overwhelmed, is a cause of cachexia or toxic shock: in humans, identical with tumor necrosis factor. Reff: www.mayoclinic.com', 'role': 'assistant'}]