The correct answer is: D. Bacillus dentificans
Bacillus dentificans is a Gram-positive, rod-shaped bacterium that is part of the normal microbiota of the oral cavity. It is a facultative anaerobe, meaning that it can grow in the presence or absence of oxygen. Bacillus dentificans is a common cause of dental caries, or tooth decay. It produces acids that demineralize tooth enamel, leading to the formation of cavities.
Nitrosomonas sp., Azotobacter sp., and Nitrobacter sp. are all nitrogen-fixing bacteria. They are able to convert atmospheric nitrogen into ammonia, which is a form of nitrogen that plants can use. These bacteria are important for the fertility of soil, as they help to increase the amount of nitrogen available for plants.
Bacillus dentificans is a different type of bacterium that does not play a role in soil fertility. It is a common cause of dental caries, and it is not beneficial to plants.