This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Physiology
[{'content': 'Thromboxane A, is produced mainly by \nSelect and explain. \nA. Vascular endothelium, B. Platelets, C. Liver, D. Damaged tissue', 'role': 'user'}, {'content': "Answer: B \nExplanation: Platelet Activating Factor(PAF) secreted by platelets act G protein-coupled receptor to produce arachidonic acid derivative like Thromboxane A2 Ref: Ganong's Review of Medical Physiology Twenty-Third Edition pg no:75 Thromboxane A2 is produced by activated platelets during hemostasis and has prothrombotic activity. It activates new platelets and increase platelet aggregation.", 'role': 'assistant'}]