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: Biochemistry
[{'content': 'Gamma-carboxylation of glutamic acid in clotting factor II, VII and protein C is dependent on \nSelect and explain. \nA. Vitamin K, B. Vitamin C, C. Vitamin A, D. Vitamin E', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Post-translational modification by γ-carboxylation of factor II, VII, IX, IX, and Proteins C and S is vitamin K dependent.', 'role': 'assistant'}]