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 A2 causes \nSelect and explain. \nA. Vasodilatation and platelet aggregaion, B. Vasodilatation and anti platelet aggregatory, C. Vasoconstriction and anti platelet aggregatory, D. Vasoconstriction and platelet aggregaion', 'role': 'user'}, {'content': "Answer: D \nExplanation: Thromboxane A2 secreted by platelets promotes platelet aggregation and vasoconstriction Ref: Ganong's Review of Medical Physiology Twenty-Third Edition Page No:563", 'role': 'assistant'}]