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
[{'content': "In cyclooxygenase (COX) pathway of the arachidonic acid (AA') metabolism, which of the following products helps to promote the platelet aggregation and vasoconstriction? \nSelect and explain. \nA. C5a, B. Thromboxane A2, C. Leukotriene B4, D. C1 activators", 'role': 'user'}, {'content': 'Answer: B \nExplanation: C5a - is anaphylatoxin and chemotactic LTB4 - is chemotactic Arachidonic acid metabolites cyclooxygenase pathway', 'role': 'assistant'}]