**Core Concept**
The parasympathetic nervous system controls various involuntary functions, including lacrimation (tear production), through a network of ganglia and nerves. The sphenopalatine ganglion is a key player in this network, specifically in regulating the lacrimal gland.

**Why the Correct Answer is Right**
The sphenopalatine ganglion is a parasympathetic ganglion located in the pterygopalatine fossa. It receives preganglionic fibers from the greater petrosal nerve, which is a branch of the facial nerve (cranial nerve VII). These fibers synapse with postganglionic neurons in the sphenopalatine ganglion, which then transmit signals to the lacrimal gland via the zygomatic nerve (a branch of the maxillary nerve). This pathway stimulates the lacrimal gland to produce tears, thereby facilitating lacrimation.

**Why Each Wrong Option is Incorrect**
* **Option A:** The otic ganglion is associated with parasympathetic innervation of the parotid gland, not lacrimation.
* **Option B:** The ciliary ganglion is involved in parasympathetic innervation of the ciliary muscle and sphincter pupillae, regulating accommodation and pupillary constriction, respectively.
* **Option D:** The Gasserian ganglion (also known as the trigeminal ganglion) is the sensory ganglion of the trigeminal nerve (cranial nerve V), primarily responsible for transmitting sensory information from the face.

**Clinical Pearl / High-Yield Fact**
The sphenopalatine ganglion is also involved in the parasympathetic innervation of the nasal mucosa, which regulates nasal secretion and mucosal blood flow. This is why the sphenopalatine ganglion is sometimes referred to as the "nasal ganglion."

**✓ Correct Answer: C. Sphenopalatine**