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': 'The Gram negative bacteria most numerous in oral cavity are \nSelect and explain. \nA. Streptococci, B. Veillonellae, C. Selenomous, D. Eikenella', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]