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: Physiology
[{'content': 'Factor IX is also called as: \nSelect and explain. \nA. Stuart power factor, B. Christmas factor, C. Prothrombin, D. Fibrin factor', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]