The correct answer is: A. Bacterias.
Chlorination is a process of adding chlorine to water to kill bacteria and other microorganisms. It is a common method of water treatment and is used to make drinking water safe. Chlorine can also be used to treat wastewater and to disinfect swimming pools.
Bacteria are single-celled organisms that can cause disease. They are found in soil, water, and the air. Some bacteria are beneficial, but others can cause illness. Chlorination kills bacteria by attacking their cell membranes.
Suspended solids are particles that are too small to be filtered out of water. They can include dirt, sand, clay, and other materials. Suspended solids can make water cloudy and can also contain harmful bacteria. Chlorination can help to remove suspended solids from water by causing them to coagulate and settle out.
Sediments are larger particles that can be filtered out of water. They can include sand, gravel, and rocks. Sediments can make water cloudy and can also contain harmful bacteria. Chlorination does not remove sediments from water.
Hardness is a measure of the amount of dissolved minerals in water. Hard water can cause scale buildup in pipes and appliances. It can also make soap less effective. Chlorination does not affect the hardness of water.