This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General pathology, Subject name: Pathology
[{'content': 'All of the following mediators of acute inflammation are derived from cells except - \nSelect and explain. \nA. Kinins, B. Cytokine, C. Histamine, D. Leukotriene', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Complement system, kinins, coagulation and fibrinolytic system are plasma protein derived. Basic Pathology, Robbins. Page no.: 45', 'role': 'assistant'}]