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': 'Co-aggregation is mainly predominated by \nSelect and explain. \nA. interaction between Gm + bacteria, B. interaction between Gm - bacteria, C. interaction between Gm + and Gm - bacteria, D. none of the above', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]