This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Arachidonic acid metabolites, Subject name: Pathology
In cyclooxygenase (COX) pathway of the arachidonic acid (AA') metabolism, which of the following products helps to promote the platelet aggregation and vasoconstriction? 
Select and explain. 
A. C5a, B. Thromboxane A2, C. Leukotriene B4, D. C1 activators
B: Thromboxane A2
Answer: B: Thromboxane A2 
Explanation: C5a - is anaphylatoxin and chemotactic LTB4 - is chemotactic Arachidonic acid metabolites cyclooxygenase pathway