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
Major mineral of the bone is 
Select and explain. 
A. Calcite, B. Hydroxyapatite, C. Calcium oxide, D. Calcium carbonate
B: Hydroxyapatite
Answer: B: Hydroxyapatite 
Explanation: Hydroxyapatite Hydroxyapatite crystals are the major mineral of bone Hydroxyapatite (also k/a bone mineral) is the salt of calcium and phosphorus with the formula Calc(PO4)6(01)2. Structural composition of bone : Also know Bone has to be 50% mineralised to be visible on radiographs.