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: Microbiology
[{'content': 'Which of the following complement act as a chemoattractant of neutrophils? \nSelect and explain. \nA. C3a, B. C3b, C. C5a, D. LTB4', 'role': 'user'}, {'content': 'Answer: C \nExplanation: C5a and the C5,6,7 complex attract neutrophils. They migrate especially well toward C5a. C5a also enhances the adhesiveness of neutrophils to the endothelium. Ref: Levinson W. (2012). Chapter 63. Complement. In W. Levinson (Ed), Review of Medical Microbiology & Immunology, 12e.', 'role': 'assistant'}]