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': 'In general, what species are predominant in supragingival tooth-associated attached plaque? \nSelect and explain. \nA. Gram-negative rods and cocci, B. Gram-negative filaments, C. Gram-positive filaments, D. Gram-positive rods and cocci', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Supragingival plaque is either tooth-associated or outer layer. Tooth-associated is composed primarily of gram-positive cocci and short rods.', 'role': 'assistant'}]