input: The following are multiple choice questions (with answers) about medical knowledge.   **Question:** A 68-year-old man presents to the emergency department because of fever, abdominal pain, and rapidly progressive distension of the abdomen. His appendix was removed for an abscess 3 days ago. The complete blood count showed leukocytosis. Anaerobic culture of the peritoneal fluid needle aspirate showed a gram-negative pathogen. Which of the following, in addition to polymicrobial infection, is the most likely cause of this patient’s condition?   (A) Bacteroides fragilis   (B) Campylobacter jejuni   (C) Clostridium perfringens   (D) Shigella sonnei
output: ['(A) Bacteroides fragilis <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) Bacteroides fragilis  (B) Campylobacter jejuni  (C) Clostridium perfringens  (D) Shigella sonnei <> possible answers', '  A 68-year-old man presents to the emergency department because of fever, abdominal pain, and rapidly progressive distension of the abdomen. His appendix was removed for an abscess 3 days ago. The complete blood count showed leukocytosis. Anaerobic culture of the peritoneal fluid needle aspirate showed a gram-negative pathogen. Which of the following, in addition to polymicrobial infection, is the most likely cause of this patient’s condition? <> context']