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: Unknown
[{'content': 'Mixed connective tissue disease includes all the following except: \nSelect and explain. \nA. Polymyositis, B. RA, C. Osteoarthritis, D. Systemic sclerosis', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Mixed connective tissue diseases (MCTD) are sometimes used to describe the disease seen in a group of patient who are identified clinically by the coexistence of features suggestive of SLE. Polymyositis, Rheumatoid arthritis and systemic sclerosis and serologically by high titres of antibodies to RNP Particle containing UI RNP. Two factors are important in lending distinctiveness to MCTD are:\nThe paucity of renal disease.\n\xa0\nExtremely good response to corticosteroid. Some important points about connective tissue disorder:\n\xa0\nAntinuclear antibodies in autoimmune disease.\n\xa0\nAnti double stranded DNA → S££ (more specific than anti SM antibody).\n\xa0\nAnti Histone Antibodies → Z)rz/g induced lupuserythrocytosis\n\xa0\nAnti sm antibody\xa0→\xa0SLE\n\xa0\nAnti DNA topoisornerasc antibody—sclerosis\n\xa0\nAntibodies of Ribonucleoprotein Antigen containing ULRNP →\xa0Mixed connective tissuedisorder.\n\xa0\nAntimitochondrial antibody → Primary biliarycirrhosis.', 'role': 'assistant'}]