This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Hematology, Subject name: Pharmacology
The drug Vorapaxar acts by primarily inhibiting Platelet aggregation caused by which of the following substance ? 
Select and explain. 
A. Thromboxane, B. ADP, C. Thrombin, D. Prostacyclin
C: Thrombin
Answer: C: Thrombin 
Explanation: VORAPAXAR: MOA : Inhibits PAR-1 receptors leading to Anti-Platelet action. On the surface of the platelets, PAR-1 receptors are present, Thrombin binds to this receptor and result in activation of platelets, so drugs are developed to inhibit this PAR-1 receptor leading Anti-Platelet action by inhibiting aggregation caused by Thrombin.