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: Surgery
Organic component of bone comprises of: 
Select and explain. 
A. 35% collagen, B. 35% noncollagenous protein, C. 65% noncollagenous protein, D. 90% collagen protein
D: 90% collagen protein
Answer: D: 90% collagen protein 
Explanation: None