worldwide vaccination for smallpox global education about smallpox better worldwide urban sanitation improved global quarantine facilities
I gave my students this multiple choice question: Which tool is most responsible for preventing future pandemics of smallpox?

Only one answer is correct among these 4 choices:
- worldwide vaccination for smallpox
- global education about smallpox
- better worldwide urban sanitation
- improved global quarantine facilities

Could you tell me which one is correct?

worldwide vaccination for smallpox