This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteriology, Subject name: Microbiology
[{'content': 'True statement about ElTor vibrio is \nSelect and explain. \nA. ElTor is more common, B. ElTor is more severe, C. ElToris associated with more carriers, D. All of the above', 'role': 'user'}, {'content': 'Answer: C \nExplanation: El Tor Vibrio:*The severity of illness- much less, with large propoion of mild and asymptomatic infections*Moality was low and the carrier rate high*El Tor vibrio tended to remain endemic in many new geographic areas, causing periodic epidemics*Proved to be much hardier than the classical vibrios, capable of surviving in the environment for much longer(Ref: Ananthanarayan 9th edition, p308)', 'role': 'assistant'}]