**Core Concept**
Thyroglossal cysts are congenital anomalies resulting from the persistence of the thyroglossal duct, which normally atrophies and obliterates during embryonic development. This cyst is a type of congenital anomaly that is closely associated with the embryological development of the thyroid gland.

**Why the Correct Answer is Right**
Thyroglossal cysts typically occur along the course of the thyroglossal duct, which runs from the foramen cecum of the tongue to the thyroid gland. The cysts usually present as a painless, movable mass in the midline of the neck, often anterior to the hyoid bone. This location is due to the fact that the thyroglossal duct usually atrophies and obliterates around the level of the hyoid bone.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the thyroglossal cyst does not typically occur in the posterior triangle of the neck, which is a common site for other types of congenital anomalies, such as branchial cleft cysts.
**Option B:** This option is incorrect because the thyroglossal cyst is not typically located in the parotid gland, which is a separate anatomical structure that is not directly related to the thyroglossal duct.
**Option C:** This option is incorrect because the thyroglossal cyst is not typically located in the parotid gland or the parotid gland region but in the midline of the neck.

**Clinical Pearl / High-Yield Fact**
Thyroglossal cysts can be easily diagnosed by feeling for a midline mass in the neck that moves upward when the patient tilts their head forward, which is a classic clinical sign of this condition.

**Correct Answer:** C. Anterior to the hyoid bone.