This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunity, Subject name: Pathology
[{'content': 'Common antibody seen in antiphospholipid syndrome: \nSelect and explain. \nA. Anticardiolipin, B. Anti-b2GPI, C. ANA, D. Anti-Sm', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. A. AnticardiolipinExplanationAnticardiolipin IgG and IgM assays are the most sensitive, but the least specific.Anti-/52GPI IgG and IgM assays are more specific but less sensitive.', 'role': 'assistant'}]