**Core Concept**
Epilepsy is a neurological disorder characterized by recurrent, unprovoked seizures due to abnormal electrical activity in the brain. This definition is crucial for diagnosis and treatment planning. The International League Against Epilepsy (ILAE) has established a classification system for epilepsy, which includes various types based on seizure frequency, etiology, and other factors.

**Why the Correct Answer is Right**
Epilepsy is defined as a disorder with recurrent, unprovoked seizures, which is a hallmark of the condition. The seizures can be partial (focal) or generalized, and may involve various brain regions, including the temporal lobe, frontal lobe, and hippocampus. The abnormal electrical activity in the brain leads to sudden changes in consciousness, muscle contractions, and other symptoms. The exact cause of epilepsy is often unknown, but it can be due to genetic mutations, brain injuries, infections, or other factors.

**Why Each Wrong Option is Incorrect**
**Option A:** This is incorrect because epilepsy is not simply characterized by a single seizure; it is a recurrent disorder.
**Option B:** While seizures can be a symptom of various neurological conditions, epilepsy is specifically defined by recurrent seizures.
**Option C:** This is incorrect because epilepsy is not solely caused by a single factor, such as genetics or brain injury; the etiology is often complex.

**Clinical Pearl / High-Yield Fact**
Recurrent, unprovoked seizures are a crucial criterion for diagnosing epilepsy. The ILAE classification system helps clinicians understand the different types of epilepsy and develop effective treatment plans.

**Correct Answer:** C.