**Core Concept**
The development of the tongue is a complex process involving the coordination of multiple embryological structures. The tongue is divided into anterior and posterior portions, each derived from different **pharyngeal arches**. Understanding the embryological origin of the tongue is crucial for comprehending its anatomy and function.

**Why the Correct Answer is Right**
The posterior one-third of the tongue, also known as the **root of the tongue**, develops from the **third and partially fourth pharyngeal arches**. This region is innervated by the **glossopharyngeal nerve (CN IX)**, which is responsible for sensory and motor functions. The development of this area is distinct from the anterior two-thirds, which originates from the **first pharyngeal arch**.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the first pharyngeal arch is responsible for the development of the anterior two-thirds of the tongue.
**Option B:** This option is also incorrect as the second pharyngeal arch contributes to the formation of the **palatine tonsils** and not the posterior tongue.
**Option D:** This is incorrect because, although the fourth pharyngeal arch does contribute to the development of the posterior tongue, it is not the sole contributor.

**Clinical Pearl / High-Yield Fact**
The posterior one-third of the tongue is clinically significant due to its innervation by the **glossopharyngeal nerve**, which can be involved in conditions such as **glossopharyngeal neuralgia**.

**Correct Answer:** C. third pharyngeal arch.