This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Clotting system, Subject name: Pathology
Activated protein C inhibit clotting mechanism by inactivating which of the following clotting factors: 
Select and explain. 
A. Factor IIIa and Factor VIIIa, B. Factor VIIIa and Factor IXa, C. Factor Va and Factor VIIIa, D. Factor Va and Factor VIIa
C: Factor Va and Factor VIIIa
Answer: C: Factor Va and Factor VIIIa 
Explanation: Protein-C is a vitamin K-dependent protease that requires a cofactor (Protein S). Activated Protein C/protein S forms a complex which is a potent inhibitor of coagulation factors Va and Factor VIIIa. Protein C acts as a Tissue factor pathway inhibitor (TFPI)