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
[{'content': 'Which of the following is not a vasodilator? \nSelect and explain. \nA. PGI2, B. Lipoxin, C. Leukotriene C4, D. PGE2', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Thromboxane A2, Leukotrienes C4, D4, E4 are vasoconstrictors. PGI2, PGE1, PGE2, PGD2 and lipoxins are vasodilators.Ref: Robbins Basic Pathology, 7th Edition, Page 48.', 'role': 'assistant'}]