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 of the following is NOT a "Chemoattractant". 
Select and explain. 
A. Leukotriene B 4, B. IL8, C. C5a, D. C3
D: C3
Answer: D: C3 
Explanation: C3