The following are multiple choice questions (with answers) about medical knowledge.   **Question:** An otherwise healthy 25-year-old woman comes to the physician because of a 2-day history of pain and swelling of her right knee joint and left wrist. She went camping with her new boyfriend 3 weeks ago but does not recall any tick bites. Her temperature is 37.8°C (100.0°F). Examination of the right knee shows swelling, warmth, and tenderness on passive movement. There is a tender pustule on the sole of the left foot. Arthrocentesis of the right knee joint yields 8 mL of cloudy fluid with a leukocyte count of 45,000/mm3 (90% segmented neutrophils with intracellular organisms). Which of the following is the strongest risk factor for this patient's condition?   (A) Autoantibody production   (B) Intravenous drug use   (C) Sexually transmitted infection   (D) HLA-B 27 positivity
['(C) Sexually transmitted infection <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) Autoantibody production \n (B) Intravenous drug use \n (C) Sexually transmitted infection \n (D) HLA-B 27 positivity <> possible answers', "  An otherwise healthy 25-year-old woman comes to the physician because of a 2-day history of pain and swelling of her right knee joint and left wrist. She went camping with her new boyfriend 3 weeks ago but does not recall any tick bites. Her temperature is 37.8°C (100.0°F). Examination of the right knee shows swelling, warmth, and tenderness on passive movement. There is a tender pustule on the sole of the left foot. Arthrocentesis of the right knee joint yields 8 mL of cloudy fluid with a leukocyte count of 45,000/mm3 (90% segmented neutrophils with intracellular organisms). Which of the following is the strongest risk factor for this patient's condition? <> context@"]