In order to prevent spreading of a communicable disease like cholera it is necessary to

The correct option is C Educate people to drink boiled water and not to eat exposed food
Cholera is an infectious disease, that causes severe watery diarrhea, which can lead to dehydration and even death if untreated. It is caused by eating food or drinking water contaminated with a bacterium, called Vibrio cholerae. The disease is most common in places with poor sanitation, crowding, war, and famine. Educate people to drink boiled water and not to eat exposed food is one of the preventive measure.

So, the correct answer is option B.