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
The bacteria responsible for causing nursing bottle caries are: 
Select and explain. 
A. Streptococcus, Lactobacillus and Veillonella, B. Lactobacillus only, C. Streptococcus, Lactobacillus and Neisseria, D. Streptococcus and Lactobacillus
A: Streptococcus, Lactobacillus and Veillonella
Answer: A: Streptococcus, Lactobacillus and Veillonella 
Explanation: Streptococcus mutans is an important pathogen in the development of dental caries. The microorganisms are usually not detectable in the mouths of infants until the later stage of incisor emergence. The main source of S. mutans is usually the mother.
Other microorganisms like Lactobacillus, Veillonella are also responsible for the nursing bottle dental caries.