Explanation:

- Option 1: Dracunculiasis

- Also known as Guinea worm disease.

- Nearly eradicated due to global efforts, but not yet complete.

- Option 2: Chickenpox

- Common childhood disease.

- Vaccines have helped control it but not eradicated.

- Option 3: Plague

- Known for its historical impact, like the Black Death.

- Controlled through antibiotics but still present in some areas.

- Option 4: Smallpox

- Declared eradicated in 1980 by the World Health Organization.

- The only human disease to be completely eradicated.