Explanation:

- Epilepsy is a neurological disorder marked by sudden, recurrent episodes of sensory disturbance, loss of consciousness, or convulsions, associated with abnormal electrical activity in the brain.

- Correct Answer: Option 3 - Epilepsy

- Insomnia refers to the inability to sleep, which can result in tiredness and other health issues but not involuntary falling unconscious.

- Senility is associated with the decline of mental faculties due to old age, and it doesn't directly cause unconsciousness.

- Dementia is a syndrome characterized by severe decline in memory and cognitive function, typically occurring in older adults, but it doesn’t cause people to fall unconscious involuntarily.