This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
[{'content': 'Of the following four bacterial species, which is LEAST\nLIKELY to be found in plaque? \nSelect and explain. \nA. Actinomyces viscosus, B. Streptococcus mutans, C. Streptococcus salivarius, D. Streptococcus sanguis', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]