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
Bacteria in plaque are held together by 
Select and explain. 
A. Hydrophobic forces, B. Covalent bonds, C. Vander waal's forces, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: None