**Core Concept**
The parotid salivary gland receives secretomotor innervation, which is a crucial aspect of salivary secretion regulation. This innervation involves the autonomic nervous system, specifically the parasympathetic division, which promotes salivation.

**Why the Correct Answer is Right**
The secretomotor fibers to the parotid gland originate from the glossopharyngeal nerve (cranial nerve IX). These fibers synapse in the otic ganglion, which is a parasympathetic ganglion located near the foramen ovale. The postganglionic fibers then travel via the lesser petrosal nerve to reach the parotid gland, where they stimulate salivary secretion. This process is mediated by the release of acetylcholine, a neurotransmitter that activates muscarinic receptors on the salivary gland cells.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the submandibular ganglion is associated with the submandibular salivary gland, not the parotid gland.
**Option B:** This option is incorrect because the pterygopalatine ganglion is involved in the innervation of the lacrimal gland and the mucous glands of the nasal and oral cavities, not the parotid gland.
**Option C:** This option is incorrect because the ciliary ganglion is associated with the parasympathetic innervation of the eye, specifically the sphincter pupillae and ciliary muscles, not the parotid gland.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that the secretomotor innervation of the parotid gland involves the glossopharyngeal nerve and the otic ganglion, which is a key landmark for identifying this innervation pattern. This knowledge is crucial for understanding salivary gland function and its regulation in various clinical contexts.

**Correct Answer:** C. Otic ganglion.