Different nerves are marked in the given diagram. Which of the following nerve supplies posterior cricoarytenoid?

**Core Concept**
The posterior cricoarytenoid muscle is the only abductor of the vocal cords, and its innervation is crucial for understanding the neural control of voice production. The **recurrent laryngeal nerve** and the **superior laryngeal nerve** are key branches of the **vagus nerve** that supply the laryngeal muscles.

**Why the Correct Answer is Right**
The **recurrent laryngeal nerve** is responsible for innervating all the intrinsic muscles of the larynx except for the cricothyroid, which is supplied by the **external branch of the superior laryngeal nerve**. The posterior cricoarytenoid muscle, being an intrinsic muscle of the larynx (other than the cricothyroid), is thus supplied by the **recurrent laryngeal nerve**.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not correspond to the nerve supply of the posterior cricoarytenoid muscle.
**Option B:** This option is incorrect as it is not related to the specific nerve supply of the posterior cricoarytenoid.
**Option D:** This is also incorrect as the specific nerve was not identified in the query.

**Clinical Pearl / High-Yield Fact**
Remember, the **recurrent laryngeal nerve** supplies all intrinsic laryngeal muscles except the cricothyroid, making it crucial for voice production and laryngeal function.

**Correct Answer:** Correct Answer: C. Recurrent Laryngeal Nerve