The correct answer is: B. Saprophytic
Saprophytic bacteria are bacteria that feed on dead or decaying organic matter. They are found in soil, water, and on the skin of animals. Saprophytic bacteria are important in the decomposition of organic matter and the recycling of nutrients.
Parasitic bacteria are bacteria that live on or in other living organisms (hosts) and obtain nutrients from them. They can cause disease in their hosts.
Pathogenic bacteria are bacteria that can cause disease in humans or other animals.
Anaerobic bacteria are bacteria that can live and grow in the absence of oxygen. They are found in environments such as sewage treatment plants, swamps, and the intestines of animals.
Saprophytic bacteria are the most common type of bacteria found in sewage. They are responsible for the decomposition of organic matter in sewage, which helps to reduce the amount of pollution in the environment.