**Core Concept**
The styloglossus muscle is one of the extrinsic muscles of the tongue, playing a crucial role in its movement and positioning within the oral cavity. This muscle is innervated by the hypoglossal nerve (CN XII) and is involved in the complex coordination of tongue movements.

**Why the Correct Answer is Right**
The styloglossus muscle originates from the styloid process of the temporal bone and inserts into the lateral surface of the tongue. As it contracts, it pulls the tongue posteriorly (backward), thereby aiding in the retraction of the tongue. This action is essential for tasks such as swallowing and speech. The styloglossus muscle works in conjunction with other extrinsic muscles to facilitate precise tongue movements.

**Why Each Wrong Option is Incorrect**
**Option A:** Protrusion of the tongue is primarily facilitated by the genioglossus muscle, not the styloglossus. The styloglossus muscle does not contribute significantly to tongue protrusion.
**Option C:** Depression of the tongue is mainly achieved by the geniohyoid and mylohyoid muscles, which are part of the floor of the mouth musculature.
**Option D:** Elevation of the tongue is primarily facilitated by the hyoglossus and geniohyoid muscles, which work together to elevate the tongue.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that the styloglossus muscle is one of the few muscles that can retract the tongue, and it plays a crucial role in swallowing and speech. This knowledge can be helpful in diagnosing and managing patients with tongue disorders or neurological conditions affecting tongue movement.

**✓ Correct Answer: B. Posteriorly retracts the tongue**