Under What Circumstances Does Cholera Typically Occur

Under what circumstances does cholera typically occur?

A) In situations of poor sanitation and crowding, as in underdeveloped countries and after natural disasters.
B) It is fairly common worldwide and outbreaks occur randomly.
C) When immigrants move to a new country, particularly if they're from an underdeveloped country.
D) Cholera outbreaks no longer occur.
E) Anywhere you have crowds of people living together.