The inorganic components of bone consist of

Analyze the question: It asks which minerals make up the inorganic (mineral) part of bone.

Explain the concept: Bone has two parts:

• Organic part: collagen fibres and bone cells, which give flexibility and toughness.
• Inorganic part: mineral salts, which give hardness and rigidity.

The main mineral in bone is calcium phosphate, which forms hydroxyapatite crystals. Bone also contains smaller amounts of calcium carbonate, magnesium salts, and traces of sodium, potassium, and fluoride.

Step-by-step solution:

1. The dominant inorganic compound is calcium phosphate, so calcium and phosphorus must both be present.
2. This eliminates A (no phosphorus) and D (no phosphorus).
3. That leaves B (magnesium, phosphorus, calcium) and C (sodium, phosphorus, calcium).
4. Both contain calcium and phosphorus, so the difference is magnesium versus sodium. Magnesium is a standard component of bone mineral in school textbooks, which list calcium, phosphorus, and magnesium salts as bone minerals. Sodium is present only in trace amounts and is more associated with body fluids.
5. So the best answer is B.

Tip: Remember "Ca-P-Mg make bone strong." Whenever you see a bone-minerals question, look first for calcium and phosphorus together, then pick the option that includes magnesium.