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
[{'content': 'Activated protein C inhibit clotting mechanism by inactivating which of the following clotting factors: \nSelect and explain. \nA. Factor IIIa and Factor VIIIa, B. Factor VIIIa and Factor IXa, C. Factor Va and Factor VIIIa, D. Factor Va and Factor VIIa', 'role': 'user'}, {'content': 'Answer: C \nExplanation: 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)', 'role': 'assistant'}]