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 cells, which are responsible for removal of bone matrix in bone resorption, are 
Select and explain. 
A. Osteoblast, B. Fibrocytes, C. Polymorphs, D. Osteoclasts
D: Osteoclasts
Answer: D: Osteoclasts 
Explanation: None