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: Microbiology
[{'content': 'All are true about Shigella except - \nSelect and explain. \nA. Large dose is required for infection, B. Associated with hemolytic uremic Syndrome, C. Causes bloody diarrhea with mucus, D. Gut pathology is due to toxin.', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]