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
Specific plaque hypothesis state that 
Select and explain. 
A. All plaque is pathogenic, B. Only specific micro-organisms are responsible for pathogenicity of plaque, C. Only specific microbes cause caries, D. Plaque is pathogenic only when signs of associated disease are present
D: Plaque is pathogenic only when signs of associated disease are present
Answer: D: Plaque is pathogenic only when signs of associated disease are present 
Explanation: None