**Core Concept**
Passavant's ridge is a mucosal fold in the nasopharynx that plays a crucial role in the physiology of swallowing and speech. It is a critical anatomical structure formed by the elevation of the superior constrictor muscle of the pharynx.

**Why the Correct Answer is Right**
Passavant's ridge is formed by the contraction of the superior constrictor muscle of the pharynx, specifically the part that is attached to the pterygoid hamulus. This muscle contraction elevates the mucosa of the nasopharynx, creating the ridge. The superior constrictor muscle is innervated by the pharyngeal plexus, which receives nerve fibers from the glossopharyngeal nerve (IX) and the vagus nerve (X). During swallowing, the contraction of Passavant's ridge helps to prevent food from entering the nasal cavity.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify the correct muscle involved in forming Passavant's ridge.
**Option B:** This option is incorrect because it does not accurately describe the anatomical structure of Passavant's ridge.
**Option C:** This option is incorrect because it does not relate to the formation of Passavant's ridge.

**Clinical Pearl / High-Yield Fact**
Passavant's ridge is an important anatomical landmark in the nasopharynx, and its elevation during swallowing helps to prevent nasal regurgitation of food. Understanding the physiology of this structure is crucial for diagnosing and managing swallowing disorders.

**Correct Answer:** D.