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
periochip is made up of: 
Select and explain. 
A. Glutaraldehyde, B. Glycerine and water, C. 2.5 mg of chlorhexidine, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: None