**Core Concept**
Woodruff's plexus is a group of lymphatic vessels and nerves that play a crucial role in the drainage of the nasal cavity and paranasal sinuses. It is located at the base of the nasal septum, near the sphenopalatine foramen.

**Why the Correct Answer is Right**
Woodruff's plexus is formed by the union of the nasal branches of the maxillary artery and the nasal branches of the sphenopalatine artery. These vessels then drain into the pterygoid venous plexus, which eventually empties into the facial vein and then into the internal jugular vein. The nerves accompanying these vessels are derived from the maxillary nerve (V2), which provides sensory innervation to the nasal cavity and paranasal sinuses.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because Woodruff's plexus is not located in the nasopharynx, which is the area above the soft palate.
**Option B:** Incorrect because Woodruff's plexus is not located in the oropharynx, which is the area behind the mouth.
**Option C:** Incorrect because Woodruff's plexus is not located in the oral cavity, which is the area inside the mouth.

**Clinical Pearl / High-Yield Fact**
Woodruff's plexus is an important landmark in rhinology and is often involved in conditions such as nasal congestion, sinusitis, and epistaxis (nosebleeds).

**Correct Answer: C. The sphenopalatine foramen.**