Which design principle of secure cloud computing ensures that the business can resume essential operations in the event of an availability-affecting incident?

The design principle that ensures a business can resume essential operations following an incident that affects availability is disaster recovery. This principle involves strategies and processes that allow an organization to quickly recover and maintain operations after a disruptive event, such as a natural disaster, cyberattack, or hardware failure. Effective disaster recovery plans include data backup solutions, failover systems, and clearly defined procedures that help minimize downtime.

In a cloud computing context, disaster recovery is crucial, as cloud environments can also face availability risks due to outages or other incidents. Implementing robust disaster recovery procedures ensures that critical data is protected and that services can be restored promptly, minimizing impact on business operations and maintaining continuity.

The other options address different aspects of security and resource management. Resource pooling pertains to the cloud provider's ability to manage multiple customers' resources flexibly and efficiently. Access control deals with ensuring that only authorized users have the permissions to access specific resources, thus enforcing security at the user level. Session management involves maintaining and monitoring user sessions to prevent unauthorized access during active sessions. While these elements are important for overall security and operation within cloud environments, they do not specifically address the need to recover from incidents that impact availability.