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': 'The conversion of prothrombin to thrombin, the factor to participate along with calcium is: \nSelect and explain. \nA. Labile factor, B. Stable factor, C. Fibrin, D. Thromboplastin', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]