This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory system, Subject name: Pharmacology
[{'content': 'Which of the following is vitamin K dependent clotting factor \nSelect and explain. \nA. Factor 7, B. Factor 1, C. Factor 11, D. Factor 12', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Refer Gaming 21/e p 547 Vitamin K dependent factors are clotting factors 2 7 9 10 And anticlotting factors protein C and protein S', 'role': 'assistant'}]