**Core Concept**
The anterior two-thirds of the tongue is primarily responsible for detecting sweet, sour, salty, and bitter tastes, which are mediated by the trigeminal nerve. This sensation is distinct from the posterior one-third of the tongue, which is responsible for detecting umami taste.

**Why the Correct Answer is Right**
The correct answer involves the trigeminal nerve's (cranial nerve V) role in transmitting taste information from the anterior two-thirds of the tongue. This is mediated through the lingual nerve, a branch of the mandibular division of the trigeminal nerve. The lingual nerve carries taste fibers from the anterior two-thirds of the tongue to the facial nerve, which then transmits this information to the brain.

**Why Each Wrong Option is Incorrect**
* **Option A:** This is incorrect because the glossopharyngeal nerve (cranial nerve IX) is responsible for transmitting taste information from the posterior one-third of the tongue, not the anterior two-thirds.
* **Option B:** This is incorrect because the vagus nerve (cranial nerve X) is primarily responsible for transmitting taste information from the epiglottis and the pharynx, not the tongue.
* **Option C:** This is incorrect because the facial nerve (cranial nerve VII) is responsible for transmitting taste information from the anterior two-thirds of the tongue, but it receives this information from the lingual nerve, not directly from the tongue.

**Clinical Pearl / High-Yield Fact**
The trigeminal nerve is also responsible for transmitting sensory information from the face, including pain, temperature, and touch. Damage to the lingual nerve can result in altered taste sensation and diminished sensation to pain and temperature in the anterior two-thirds of the tongue.

**Correct Answer:** C. Facial nerve. Facial nerve.