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
In general, what species are predominant in supragingival tooth-associated attached plaque? 
Select and explain. 
A. Gram-negative rods and cocci, B. Gram-negative filaments, C. Gram-positive filaments, D. Gram-positive rods and cocci
D: Gram-positive rods and cocci
Answer: D: Gram-positive rods and cocci 
Explanation: Supragingival plaque is either tooth-associated or outer layer. Tooth-associated is composed primarily of gram-positive cocci and short rods.