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
Traveller's diarrhea is caused by 
Select and explain. 
A. Shigella, B. E.coli, C. E.histolytica, D. Giardiasis
B: E.coli
Answer: B: E.coli 
Explanation: 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)