From the Bacteria's Perspective, Why Is It Helpful That It

From the bacteria's perspective, why is it helpful that it produce diarrhea in people?

A) Because that quickly kills the person
B) Because there is no real treatment for that
C) Because it makes the patient too unpleasant to be around
D) Because it gets the bacteria out of the person and, likely, into the next one
E) It's not helpful really. That's just what that toxin causes.