This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
[{'content': 'Which is not involved in local hemostasis \nSelect and explain. \nA. Fibrinogen, B. Calcium, C. Vit k, D. Collagen', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ref Robbins 9/e p118-119 Vitamin K serves as an essential cofactor for a carboxylase that catalyzes carboxylation of glutamic acid residues on vitamin K-dependent proteins. The key vitamin K-dependent proteins include: Coagulationproteins: factors II (prothrombin), VII, IX and X', 'role': 'assistant'}]