Who was notified by the CDC about the smallpox vials found?

The correct answer is that the World Health Organization (WHO) was notified by the CDC about the discovery of the smallpox vials. The WHO plays a crucial role in global health governance and coordination, particularly concerning eradicated diseases such as smallpox. Given its responsibility to oversee the global status of health issues and ensure that potentially dangerous pathogens are handled appropriately, notifying the WHO aligns with the established protocol for managing and securing such high-risk biological threats.

The other entities listed, such as the FDA and NIH, have significant roles in health and medicine but do not possess the same global oversight function as the WHO in relation to disease eradication and management on a worldwide scale. While the CDC would contact relevant organizations to ensure public safety and compliance, the primary notification for an event with global implications, such as finding smallpox vials, would appropriately be directed towards the WHO. This distinguishes the unique role of international cooperation in emergency health situations.