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
[{'content': 'Chemotaxis is promoted by the all except - \nSelect and explain. \nA. Lymphokine, B. Kallikerine, C. Serotonin, D. Complement factor', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e., Serotonin", 'role': 'assistant'}]