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
Which of the following is act as a procoagulation protein? 
Select and explain. 
A. Thrombomodulin, B. Protein C, C. Protein S, D. Thrombin
D: Thrombin
Answer: D: Thrombin 
Explanation: Procoagulation proteins serve as a precursor of various blood factors necessary for coagulation. Thrombin/ Factor II is a procoagulation protein because it conves the soluble plasma protein fibrinogen into insoluble fibrous protein fibrin. Thrombin also induce recruitment of platelet and induce release of granules from them. Ref: Robbins Pathologic Basis of Disease 6th Edition, Page 119, 120