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: Pathology
For a bacterium to be seriously considered in the etiology of dental caries, it must: 
Select and explain. 
A. Exist regularly in the dental plaque, B. Produce extracellular amylopectins, C. Be lethal for gnotobiotic animals, D. Produce intracellular dextrans
A: Exist regularly in the dental plaque
Answer: A: Exist regularly in the dental plaque 
Explanation: None