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
Organisms involved in pit and fissure caries: 
Select and explain. 
A. Streptococcus mutans., B. Lactobacillus., C. Actinomyces., D. All of the above.
D: All of the above.
Answer: D: All of the above. 
Explanation: Pit & fissure caries in initiated by a wide variety of organisms like S. mutans, Lactobacillus and Actinomyces species as they colonize in these retentive areas. However, only S.mutans (very significantly) & S. salivarius (by chance) have been proved to colonise smooth surfaces.