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: Pathology
[{'content': 'Serum contains all the clotting factors, except \nSelect and explain. \nA. Plasma thromboplastin, B. Labile factor, C. Hageman factor, D. Christmas factor', 'role': 'user'}, {'content': 'Answer: B \nExplanation: If whole blood is allowed to clot and the clot is removed, the remaining fluid is called serum. Serum has essentially the same composition as plasma, except that:\n\nFibrinogen (factor I) and clotting factors II, V, and VIII have been removed and\nHas higher serotonin content, because of the breakdown of platelets during clotting.\n\nAlso, know that factor 5 is called as labile factor.', 'role': 'assistant'}]