Answer :
Answer;
d. bacterial.
Explanation;
-When water is polluted, it becomes unsafe for human consumption because the water contains dangerous or toxic substances and disease-causing bacteria and organisms. Pollution may be caused by natural sources or human activities, but regardless of the cause, the result is the same.
-Dumping raw sewage directly into the bay results to water pollution, by bacteria and other disease causing micro-organisms. The microorganisms that can cause harmful diseases are called pathogenic. Therefore, opening a new waste water treatment plant in an area, reduces bacterial type of pollution.
The correct answer is option D
The wastewater treatment plant opens in an area where the raw sewage having bacteria is treated by the waste water plant.
The sewage will contain many types of harmful bacteria in it. These bacteria can cause diseases like diarrhea, malaria, et cetera.
These bacteria are removed by the waster water treatment plant.