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': "Traveller's diarrhea is caused by \nSelect and explain. \nA. Shigella, B. E.coli, C. E.histolytica, D. Giardiasis", 'role': 'user'}, {'content': "Answer: B \nExplanation: Diarrheal strains of E.coli:Strain of E.coliDiseaseETEC Traveller's diarrhea EPEC Watery diarrhea in young children EIEC Dysentery EAEC Traveller's diarrhea / Persistent diarrhea (Ref: Ananthanarayan 9th edition, p279)", 'role': 'assistant'}]