You will be given a definition of a task first, then some input of the task.
In this task, you are given a multiple-choice question about healthcare. Answer the question based on your information and classify your answers into '1', '2', '3', and '4'.

Question: Thermolabile (LT) and thermostable (ST) enterotoxins are responsible for diarrhea caused by some strains of:
Options: <1> Salmonella enterica <2> Vibrio cholerae <3> Campylobacter jejuni. <4> Yersinia enterocolitica. <5> Escherichia coli
Output:
5