This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: NEET 2019, Subject name: Pathology
Which one of following is functions of PGI2? 
Select and explain. 
A. Vasoconstriction and inhibits platelet aggregation, B. Vasodilator and inhibits platelet aggregation, C. Vasoconstriction and increases platelet aggregation, D. Vasodilator and increases platelet aggregation
B: Vasodilator and inhibits platelet aggregation
Answer: B: Vasodilator and inhibits platelet aggregation 
Explanation: The most impoant PG ones in inflammation are:-PGE2, PGD2, PGF2a, PGI2 (prostacyclin), and TxA2 (thromboxane A2), each of which is derived by the action of a specific enzyme on an intermediate in the pathway. Note:-A thromboxane-prostacyclin imbalance has been implicated as an early event in thrombus formation in coronary and cerebral blood vessels.