**Core Concept:** The hyoid bone is a unique bone in the human body that does not fuse with any other bones during growth. It is a horseshoe-shaped bone located in the neck, supporting the tongue and holding the tongue away from the trachea. The number of ossification centres for the hyoid bone is crucial for understanding its development and differentiation from other bones.

**Why the Correct Answer is Right:** The correct answer is **D. 4** because the hyoid bone undergoes four ossification centres during its development:

1. One centre in the body of the bone
2. Two centres on the anterior surface of the body near the extremities
3. One centre in the posterior surface of the body

This process of ossification results in the horseshoe-shaped structure with four ossification centres that is characteristic of the hyoid bone.

**Why Each Wrong Option is Incorrect:**

A. **2 centres** is incorrect because the hyoid bone has four ossification centres.
B. **3 centres** is incorrect, as the correct answer is four centres.
C. **No centres** is incorrect, as the hyoid bone does have ossification centres during its development.

**Clinical Pearl:** The hyoid bone is a critical structure for maintaining proper anatomy and function of the head and neck. Abnormalities in the number of ossification centres can lead to various disorders, making understanding this concept essential for medical professionals.