The correct answer is C. Activated carbon.
Alum is a type of salt that is used to clarify water. It does not remove odors.
Bleach is a disinfectant that can be used to kill bacteria and viruses in water. It does not remove odors.
Deactivated nitrogen is a gas that is used to remove oxygen from water. It does not remove odors.
Activated carbon is a type of carbon that has been treated to have a high surface area. It is used to remove impurities from water, including odors.
When activated carbon is added to water, it adsorbs the molecules that cause the odor. This process is called adsorption. Adsorption is a physical process that occurs when molecules are attracted to the surface of a solid. The molecules that are adsorbed to the activated carbon are then removed from the water.
Activated carbon is a very effective way to remove odors from water. It is used in a variety of applications, including water treatment, air purification, and odor control.