Cholera is a disease that is spread in water. which treatment would most likely benefit society to prevent the spread of cholera?

Cholera is an infectious disease that is borne in areas with poor sanitation and overcrowding and is common in third world countries that have no access to clean and potable water. The common symptom is diarrhea and if it further leads to dehydration it can cause death to a number of individuals. The easiest way to prevent this is through the proper boiling of water if chemical disinfection and water bottles are not easily accessible.

Water that is boiled can also be used for preparing food or other drinks, making ice, brushing the teeth, washing the face and hands, washing fruits and vegetable and washing utensils properly. The temperature kills off the bacteria and is the cheapest way of preventing the further spread of cholera.  

Is that a negative 22 or a positive?

The answer is either 3 or 4