**Core Concept**
The greater petrosal nerve is a branch of the facial nerve (cranial nerve VII) that plays a crucial role in the parasympathetic innervation of the lacrimal gland and the mucous membranes of the nasal cavity and palate. It is part of the autonomic nervous system, which regulates various involuntary functions.

**Why the Correct Answer is Right**
The greater petrosal nerve is formed from the geniculate ganglion of the facial nerve. The geniculate ganglion is a sensory ganglion that contains the cell bodies of sensory neurons that transmit taste and other sensory information from the tongue and palate. The greater petrosal nerve arises from the inferior aspect of the geniculate ganglion and traverses the middle cranial fossa to reach the pterygopalatine ganglion, where it synapses with postganglionic neurons that innervate the lacrimal gland and other structures.

**Why Each Wrong Option is Incorrect**
* **Option A:** The greater petrosal nerve is not formed from the intermediate nerve, which is a branch of the facial nerve that innervates the stapedius muscle and the tympanic membrane.
* **Option B:** The greater petrosal nerve is not formed from the chorda tympani, which is a branch of the facial nerve that transmits taste information from the anterior two-thirds of the tongue.
* **Option C:** The greater petrosal nerve is not formed from the nerve to the stapedius, which is a branch of the facial nerve that innervates the stapedius muscle.

**Clinical Pearl / High-Yield Fact**
The greater petrosal nerve is an important landmark in the surgical approach to the middle cranial fossa, and damage to this nerve can result in dry eye and other complications.

**Correct Answer: B. The chorda tympani.**