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: Medicine
[{'content': 'All are included in the diagnostic criteria for clostridium difficile infection, EXCEPT: \nSelect and explain. \nA. 3 unformed stools per 24h for 2days, B. Toxin A or B detected in the stool, C. Pseudo membranes in colonoscopy, D. Fever', 'role': 'user'}, {'content': 'Answer: D \nExplanation: The diagnosis of CDI is based on: 1. Diarrhea (3 unformed stools per 24 h for 2 days) with no other recognized cause PLUS 2. Toxin A or B detected in the stool, 3. Toxin-producing C. difficile detected in the stool by polymerase chain reaction (PCR) or culture. 3. Pseudomembranes in the colon. ALSO KNOW: Endoscopy is a rapid diagnostic tool in seriously ill suspected patients A negative test does not rule out infection Ref: Harrison, Edition-18,page-1093.', 'role': 'assistant'}]