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': 'Infective dose of S.typhi is \nSelect and explain. \nA. 10 bacilli, B. 102 bacilli, C. 103-106 bacilli, D. 107-1012 bacilli', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Infective dose is\xa0103-106 colony forming units.', 'role': 'assistant'}]