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: Pharmacology
Heparin, apart from releasing lipoprotein lipase in the blood exerts its anti-coagulant action by: 
Select and explain. 
A. Binding to calcium, B. Inhibiting fibrinogen synthesis, C. Inhibiting prothrombin synthesis, D. Inhibiting thrombin synthesis
D: Inhibiting thrombin synthesis
Answer: D: Inhibiting thrombin synthesis 
Explanation: None