This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Inflammation & Repair, Subject name: Pathology
Which among the following is a vasoconstrictor? 
Select and explain. 
A. Histamine, B. PGI2, C. Bradykinin, D. TXA2
D: TXA2
Answer: D: TXA2 
Explanation: Ans. is 'd' i.e., TXA2 Important mediators* Vasodilatation Histamine, prostaglandins, prostacyclins, serotonin, Nitric oxide, bradykinin.* Vasoconstriction Leukotrienes (LTC4, D4, E4), Thromboxane A2.