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': 'Loose fibrin accumulated in tight clot in coagulation pathway by factor ? \nSelect and explain. \nA. X, B. XI, C. XII, D. XIII', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., XIII Loose (soluble) fibrin is conveed to insuluble fibrin by thrombin and XIIIa.", 'role': 'assistant'}]