This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Breast, Subject name: Pathology
[{'content': 'Rheumatoid factor Is- \nSelect and explain. \nA. Antibody, B. Mucopolysaccharide, C. Fatty acid, D. Glycoprotein', 'role': 'user'}, {'content': 'Answer: A \nExplanation: In 80%of the cases of Rheumatoid ahritis have serum IgM autoantibodies that bind to fc poion of their own self IgG. These antibodies are called rheumatoid factor. Howeever the role of Rheumatoid factor in the Pathogenesis of the joint or extra aicular lesions has not been established. Ref:Robbins basic pathology 9th edition page no 784,green box =Pathogenesis', 'role': 'assistant'}]