This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Skin, Bones and Joints, Subject name: Pathology
[{'content': 'Which of the following is the most specific test for Rheumatoid ahritis: \nSelect and explain. \nA. Anti-CCP antibody, B. Anti Igm antibody, C. Anti IgA antibody, D. Anti IgG antibody', 'role': 'user'}, {'content': 'Answer: A \nExplanation: RF and anti-CCP antibodies, may be found in sera from patients many years before clinical disease can be detected', 'role': 'assistant'}]