## Core Concept
The taste sensation of the tongue is mediated by specific cranial nerves. The **chorda tympani nerve**, a branch of the facial nerve (cranial nerve VII), is responsible for transmitting taste sensations from the anterior two-thirds of the tongue.

## Why the Correct Answer is Right
The facial nerve (cranial nerve VII) has a branch called the **chorda tympani**, which carries taste fibers from the anterior 2/3rd of the tongue. These fibers synapse in the **nucleus of the solitary tract** in the brainstem before being relayed to higher centers for taste perception. This specific innervation allows for the sensation of sweet, sour, salty, and bitter tastes in this region.

## Why Each Wrong Option is Incorrect
* **Option A:** The **glossopharyngeal nerve (cranial nerve IX)** carries taste sensation from the posterior one-third of the tongue, not the anterior 2/3rd.
* **Option B:** The **trigeminal nerve (cranial nerve V)** is primarily responsible for sensory innervation of the face, including pain, temperature, touch, and proprioception, but not taste.
* **Option D:** The **vagus nerve (cranial nerve X)** carries taste sensation from the epiglottis and the back of the throat, not the tongue.

## Clinical Pearl / High-Yield Fact
A key clinical correlation is that damage to the **chorda tympani nerve** can result in altered taste sensation (dysgeusia) in the anterior 2/3rd of the tongue. This can occur due to middle ear infections or surgical trauma.

## Correct Answer Line
**Correct Answer: C. Facial nerve (Chorda tympani)**