## **Core Concept**
The core concept being tested here is the historical eradication of smallpox, a highly infectious and often fatal disease caused by the variola virus. Smallpox was targeted by a global vaccination campaign led by the World Health Organization (WHO), which ultimately resulted in its eradication. Understanding the timeline of this eradication effort is crucial for appreciating the significance of vaccination in public health.

## **Why the Correct Answer is Right**
The correct answer, . 1977, marks the year when the last naturally occurring case of smallpox was reported. This case was identified in Somalia, and it was a significant milestone in the global campaign to eradicate smallpox. The WHO officially declared smallpox eradicated in 1980, following a global vaccination effort that began in 1959. The eradication of smallpox stands as a monumental achievement in the history of medicine and public health.

## **Why Each Wrong Option is Incorrect**
- **Option A:** . 1980 - This is the year the WHO officially declared smallpox eradicated, not the year the last case was reported.
- **Option B:** . 1960 - This is too early, as the global vaccination campaign against smallpox was just beginning to gain momentum around this time.
- **Option C:** . 1990 - This is too late, as the last naturally occurring case had already been reported in 1977.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that smallpox was eradicated through a global vaccination effort led by the WHO. The last naturally occurring case of smallpox was reported in 1977 in Somalia. This achievement demonstrates the power of coordinated public health efforts and vaccination in eliminating infectious diseases.

## **Correct Answer:** . 1977