What presents the greatest health risk to a person living in a developing country? 

A)  unsanitary drinking water 
B)  diabetes 
C)  hantavirus 
D)  Ebola virus

Unsantitary drinking water is a major health risk in developing countries as it can lead to a wide range of waterborne illnesses such as cholera, typhoid fever, and dysentery. Access to clean drinking water is often limited or non-existent in developing countries, leading to high rates of illness and even death. Diabetes, hantavirus, and Ebola virus are all serious health risks, but they may not be as widespread or prevalent in developing countries as unsanitary drinking water.