Final answer:
When a data center is flooded, causing the EHR to become inoperable, the type of security that has failed is physical security. Physical security involves protective measures against real-world events that can harm the physical assets.
Step-by-step explanation:
The type of security that failed in the scenario where a data center containing the computer with the electronic health record (EHR) was flooded is physical security. Physical security is concerned with protecting the physical assets of an organization, such as its facilities and hardware, from real-world events like natural disasters, theft, or sabotage. In this case, proper physical security measures might have included waterproof barriers, elevated hardware, or an alternative backup location to prevent damage from flooding. The failure to protect the data center from flooding resulted in the EHR becoming inoperable, demonstrating a breach in physical security.