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': 'The most common cause of "Antibiotic" induced colitis is due to: \nSelect and explain. \nA. E. coli, B. Clostridium difficile, C. Salmonella, D. Campylobacter jejuni', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Clostridium difficile', 'role': 'assistant'}]