**Core Concept**
The anterior digastric triangle is a region in the neck bounded by the anterior belly of the digastric muscle, the mandible, and the mylohyoid muscle. This triangle is significant due to the structures it contains, particularly those superficial to the mylohyoid muscle.

**Why the Correct Answer is Right**
The correct answer involves identifying structures that lie superficial to the mylohyoid muscle within the anterior digastric triangle. The mylohyoid artery and nerve are key structures in this region. The mylohyoid artery is a branch of the inferior alveolar artery, which arises from the maxillary artery. This artery supplies the mylohyoid muscle and the floor of the mouth. The mylohyoid nerve, a branch of the inferior alveolar nerve, provides motor innervation to the mylohyoid muscle. Both the mylohyoid artery and nerve are critical for the function and sensation of the muscles in the floor of the mouth.

**Why Each Wrong Option is Incorrect**
**Option A:** The deep part of the submandibular gland lies beneath the mylohyoid muscle, not superficial to it. This gland is responsible for the production of saliva and is a key structure in the oral cavity.
**Option B:** The hypoglossal nerve primarily supplies the muscles of the tongue and is not a structure superficial to the mylohyoid muscle in the anterior digastric triangle.
**Option C:** The parotid gland is located in the parotid triangle, which is a different region from the anterior digastric triangle.

**Clinical Pearl / High-Yield Fact**
In the anterior digastric triangle, the mylohyoid artery and nerve are key structures that are easily palpable and can be an important landmark for surgeons and anatomists. The knowledge of these structures is crucial for various procedures, including dental and oral surgeries.

**✓ Correct Answer: D. Mylohyoid artery & nerve**