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
Fondaparinux is an anticoagulant that acts by inhibiting 
Select and explain. 
A. Factor Xa more than factor II, B. Both factor Xa and factor II equally, C. Only factor Xa, D. Only factor II
C: Only factor Xa
Answer: C: Only factor Xa 
Explanation: Fondaparinux is a synthetic congener of Heparin containing only active pentasaccharide unit and inhibits only Xa. It doesn't inhibit thrombin (factor II a).