Which of the following disease has been completely eradicated?

Options

A. Plague
B. Poliomelities
C. Smallpox
D. Kala-azar

Answer

**Step-by-Step Solution:**

1. **Identify the Diseases Listed**: The question presents four diseases: plague, poliomyelitis, smallpox, and sclerosis. We need to determine which of these has been completely eradicated.

2. **Understand the Concept of Eradication**: A disease is considered eradicated when there are no longer any cases of the disease occurring anywhere in the world.

3. **Evaluate Each Disease**:
- **Plague**: This disease is still present in some parts of the world and has not been eradicated.
- **Poliomyelitis**: Efforts are ongoing to eradicate this disease, but it has not been completely eliminated yet.
- **Smallpox**: This disease has been declared completely eradicated since 1980, following a successful global vaccination campaign.
- **Sclerosis**: This is not an infectious disease and is not subject to eradication in the same way that infectious diseases are.

4. **Conclusion**: Based on the evaluation, the only disease that has been completely eradicated is smallpox.

5. **Final Answer**: The disease that has been completely eradicated is **smallpox**.

---