question: Q:A 46-year-old woman comes to the physician with a 4-month history of lethargy. She has had joint pain for the past 15 years and does not have a primary care physician. Her temperature is 37.4°C (99.3°F), pulse is 97/min, and blood pressure is 132/86 mm Hg. Physical examination shows pallor of the oral mucosa and nontender subcutaneous nodules on both elbows. The distal interphalangeal joints of both hands are flexed and the proximal interphalangeal joints appear hyperextended. Range of motion in the fingers is restricted. The liver span is 6 cm and the spleen tip is palpated 4 cm below the left costal margin. Laboratory studies show:
  Hematocrit 33%
  Leukocyte count 1,800/mm3
  Segmented neutrophils 35%
  Lymphocytes 60%
  Platelet count 130,000/mm3
  Increased serum titers of which of the following is most specific for this patient's condition?"? 
  {'A': 'Anti-CCP antibody', 'B': 'Anti-Sm antibody', 'C': 'Antinuclear antibody', 'D': 'Rheumatoid factor', 'E': 'Anti-U1-RNP antibody\n"'},