Virulent microbes, which are transmitted mainly through drinking water, are the most common cause of waterborne diseases. According to the World Health Organization, such diseases cause almost two million deaths every year, and an estimated 65 percent of these fatalities are caused by microbial organisms. Clearly, this number can be significantly reduced if drinking water is treated with anti-microbial agents before it is supplied to consumers.
Which of the following would it be most useful to establish in order to evaluate the conclusion drawn above?
A. Whether treating drinking water with anti-microbial agents would be more expensive than treating it with conventional water purification processes
B. Whether the fatalities caused by waterborne diseases would be reduced if alternative forms of medical treatment were used
C. Whether the figures reported by the World Health Organization include the number of deaths caused by allergic reactions to medicines prescribed for the treatment of waterborne diseases
D. Whether drinking water is contaminated at water processing plants or while being delivered to consumers
E. Whether drinking water contains any harmful contaminants other than disease-causing microbes